From 4ebe8fddcafd1028a0daea3ee98fc0a2a6d2c206 Mon Sep 17 00:00:00 2001
From: JoFrhwld <JoFrhwld@gmail.com>
Date: Sun, 8 Feb 2026 17:32:40 -0500
Subject: [PATCH 1/9] updating typing

---
 src/fasttrackpy/patterns/audio_textgrid.py | 11 ++++++-----
 src/fasttrackpy/patterns/corpus.py         | 12 +++++++-----
 src/fasttrackpy/patterns/just_audio.py     |  7 +++----
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/src/fasttrackpy/patterns/audio_textgrid.py b/src/fasttrackpy/patterns/audio_textgrid.py
index 2162e77..0fcc872 100644
--- a/src/fasttrackpy/patterns/audio_textgrid.py
+++ b/src/fasttrackpy/patterns/audio_textgrid.py
@@ -1,3 +1,4 @@
+from collections.abc import Sequence
 import parselmouth as pm
 from aligned_textgrid import AlignedTextGrid, Word, Phone, SequenceInterval, SequenceTier
 import aligned_textgrid
@@ -66,7 +67,7 @@ def get_candidates(args_dict):
 
 @delayed
 @safely(message="There was a problem getting some candidate tracks.")
-def get_candidates_delayed(args_dict):
+def get_candidates_delayed(args_dict) -> CandidateTracks:
     with warnings.catch_warnings():
         warnings.simplefilter("ignore")
         candidates =  CandidateTracks(**args_dict)
@@ -74,10 +75,10 @@ def get_candidates_delayed(args_dict):
         warnings.warn("formant tracking error")
     return candidates
 
-def run_candidates(arg_list, parallel:bool):
+def run_candidates(arg_list, parallel:bool) -> Sequence[CandidateTracks]:
     if parallel:
         n_jobs = cpu_count()
-        all_candidates = Parallel(n_jobs=n_jobs)(
+        all_candidates = Parallel(n_jobs=n_jobs, return_as="list")(
             get_candidates_delayed(args_dict=arg) for arg in tqdm(arg_list)
             )
         return all_candidates
@@ -104,7 +105,7 @@ def process_audio_textgrid(
         loss_fun: Loss = Loss(),
         agg_fun: Agg = Agg(),
         heuristics: list[MinMaxHeuristic|SpacingHeuristic] = []     
-)->list[CandidateTracks]:
+)->Sequence[CandidateTracks]:
     """Process an audio and TextGrid file together.
 
     Args:
@@ -154,7 +155,7 @@ def process_audio_textgrid(
 
     entry_classes = get_interval_classes(textgrid_format=entry_classes)
     
-    tg = AlignedTextGrid(textgrid_path=textgrid_path, entry_classes=entry_classes)
+    tg = AlignedTextGrid(textgrid=textgrid_path, entry_classes=entry_classes)
     target_tiers = get_target_tiers(tg, target_tier=target_tier)
     target_intervals = get_target_intervals(
         target_tiers=target_tiers, 
diff --git a/src/fasttrackpy/patterns/corpus.py b/src/fasttrackpy/patterns/corpus.py
index 59e2895..a4ed30b 100644
--- a/src/fasttrackpy/patterns/corpus.py
+++ b/src/fasttrackpy/patterns/corpus.py
@@ -17,6 +17,8 @@
 import os
 import sys
 
+from collections.abc import Sequence
+
 CorpusPair = namedtuple("CorpusPair", field_names=["wav", "tg"])
 
 def get_audio_files(
@@ -32,7 +34,7 @@ def get_audio_files(
 
 def get_corpus(
         audio_files:list[Path]
-        ) -> list[tuple[Path, Path]]:
+        ) -> Sequence[CorpusPair]:
     wav_tg = [
         CorpusPair(wav, wav.with_suffix(".TextGrid"))
         for wav in audio_files
@@ -42,7 +44,7 @@ def get_corpus(
 
 def read_and_associate_tg(
         corpus_pair: CorpusPair,
-        entry_classes:list[SequenceInterval] = [Word, Phone]
+        entry_classes:Sequence[type[SequenceInterval]] = [Word, Phone]
         ) -> AlignedTextGrid:
     tg = AlignedTextGrid(
         textgrid_path=str(corpus_pair.tg), 
@@ -91,8 +93,8 @@ def get_target_intervals(
 def get_sound_parts(
         intervals: list[SequenceInterval],
         window_length: float
-):
-    sound = pm.Sound(str(intervals[0].wav))
+) -> Sequence[pm.Sound]:
+    sound = pm.Sound(str(getattr(intervals[0], "wav")))
     sound_parts = [
         sound.extract_part(from_time = interval.start-(window_length/2), 
         to_time = interval.end+(window_length/2))
@@ -120,7 +122,7 @@ def get_candidates(args_dict):
         warnings.warn("formant tracking error")
     return candidates
 
-def run_candidates(arg_list, parallel:bool):
+def run_candidates(arg_list, parallel:bool) -> Sequence[CandidateTracks]:
     if parallel:
         n_jobs = cpu_count()
         all_candidates = Parallel(n_jobs=n_jobs)(
diff --git a/src/fasttrackpy/patterns/just_audio.py b/src/fasttrackpy/patterns/just_audio.py
index 402034a..5f171a2 100644
--- a/src/fasttrackpy/patterns/just_audio.py
+++ b/src/fasttrackpy/patterns/just_audio.py
@@ -1,7 +1,6 @@
 import warnings
 from pathlib import Path
-from typing import Union
-from collections.abc import Callable
+from collections.abc import Callable, Sequence
 import parselmouth as pm
 from fasttrackpy import CandidateTracks,\
                         Smoother,\
@@ -38,7 +37,7 @@ def is_audio(path: str|Path)->bool:
 def process_audio_file(
         path: str|Path,
         xmin:float = 0,
-        xmax: float = None,
+        xmax: float|None = None,
         min_max_formant:float = 4000,
         max_max_formant:float = 7000,
         nstep:int = 20,
@@ -123,7 +122,7 @@ def get_candidates_delayed(args_dict):
 def get_candidates(args_dict):
     return process_audio_file(**args_dict)
 
-def run_candidates(arg_list, parallel:bool):
+def run_candidates(arg_list, parallel:bool) -> Sequence[CandidateTracks]:
     if parallel:
         n_jobs = cpu_count()
         all_candidates = Parallel(n_jobs=n_jobs)(

From 78dcf25a5c6ef0ebc48d98b7173c0b43fd9d2453 Mon Sep 17 00:00:00 2001
From: JoFrhwld <JoFrhwld@gmail.com>
Date: Sun, 8 Feb 2026 17:34:47 -0500
Subject: [PATCH 2/9] update typing

---
 src/fasttrackpy/processors/aggs.py      |  9 ++++---
 src/fasttrackpy/processors/losses.py    | 35 +++++++++++++------------
 src/fasttrackpy/processors/smoothers.py | 12 ++++-----
 3 files changed, 29 insertions(+), 27 deletions(-)

diff --git a/src/fasttrackpy/processors/aggs.py b/src/fasttrackpy/processors/aggs.py
index 1ff24d6..67a22c0 100644
--- a/src/fasttrackpy/processors/aggs.py
+++ b/src/fasttrackpy/processors/aggs.py
@@ -1,4 +1,5 @@
 import numpy as np
+import numpy.typing as npt
 from typing import Union
 from collections.abc import Callable
 
@@ -11,7 +12,7 @@ class Agg:
 
     def __init__(
         self, 
-        method: Union[str, Callable]= "agg_sum",
+        method: str|Callable = "agg_sum",
         **kwargs
     ):
         self.method = self._get_method(method)
@@ -19,11 +20,11 @@ def __init__(
     
     def _get_method(
         self, 
-        method:Union[str, Callable]
-    ):
+        method:str|Callable[[npt.NDArray], float]
+    )->Callable:
         if callable(method):
             return method
-        if method == "agg_sum":
+        else:
             return agg_sum
     
     def aggregate(
diff --git a/src/fasttrackpy/processors/losses.py b/src/fasttrackpy/processors/losses.py
index df551a2..1da7248 100644
--- a/src/fasttrackpy/processors/losses.py
+++ b/src/fasttrackpy/processors/losses.py
@@ -1,6 +1,7 @@
 import numpy as np
-from typing import Union
+import numpy.typing as npt
 from collections.abc import Callable
+
 class Loss:
     """_summary_
 
@@ -10,7 +11,7 @@ class Loss:
 
     def __init__(
         self,
-        method: Union[str, Callable] = "lmse",
+        method: str|Callable = "lmse",
         **kwargs
     ):
         self.method = self._get_fun(method)
@@ -18,13 +19,13 @@ def __init__(
     
     def _get_fun(
             self, 
-            method: Union[str, Callable]
+            method: str|Callable 
         ) -> Callable:
         if callable(method):
             return method
-        if method == "lmse":
+        elif method == "lmse":
             return lmse
-        if method == "mse":
+        else:
             return mse
         
     def calculate_loss(
@@ -35,38 +36,38 @@ def calculate_loss(
         return self.method(formants, smoothed, **self.method_args)
     
 def lmse(
-        formants: np.ndarray, 
-        smoothed: np.ndarray, 
+        formants: npt.NDArray, 
+        smoothed: npt.NDArray, 
         axis: int = 1
-    ) -> np.ndarray:
+    ) -> npt.NDArray:
     """_summary_
 
     Args:
-        formants (np.ndarray): _description_
-        smoothed (np.ndarray): _description_
+        formants (npt.NDArray): _description_
+        smoothed (npt.NDArray): _description_
         axis (int, optional): _description_. Defaults to 1.
 
     Returns:
-        np.ndarray: _description_
+        npt.NDArray: _description_
     """
     sqe = np.power(np.log(formants) - np.log(smoothed), 2)
     mse = np.nanmean(sqe, axis = axis)
     return mse
 
 def mse(
-        formants: np.ndarray, 
-        smoothed: np.ndarray, 
+        formants: npt.NDArray, 
+        smoothed: npt.NDArray, 
         axis: int = 1
-    ) -> np.ndarray:
+    ) -> npt.NDArray:
     """_summary_
 
     Args:
-        formants (np.ndarray): _description_
-        smoothed (np.ndarray): _description_
+        formants (npt.NDArray): _description_
+        smoothed (npt.NDArray): _description_
         axis (int, optional): _description_. Defaults to 1.
 
     Returns:
-        np.ndarray: _description_
+        npt.NDArray: _description_
     """
     sqe = np.power(formants - smoothed, 2)
     mse = np.nanmean(sqe, axis = axis)
diff --git a/src/fasttrackpy/processors/smoothers.py b/src/fasttrackpy/processors/smoothers.py
index caad017..ef2537c 100644
--- a/src/fasttrackpy/processors/smoothers.py
+++ b/src/fasttrackpy/processors/smoothers.py
@@ -34,23 +34,23 @@ class Smoother:
     """
     def __init__(
         self,
-        method: Union[str, Callable] = "dct_smooth_regression",
+        method: str|Callable = "dct_smooth_regression",
         **kwargs
     ):
         self.smooth_fun = self._get_fun(method)
         self.method_args = kwargs
     
-    def _get_fun(self, method):
+    def _get_fun(self, method)->Callable:
         if callable(method):
             return method
-        if method == "dct_smooth":
+        elif method == "dct_smooth":
             return dct_smooth
-        if method == "dct_smooth_regression":
+        else: 
             return dct_smooth_regression
         
     def smooth(
             self, 
-            x: np.array
+            x: npt.NDArray
         ) -> Smoothed:
         """Apply the smoother function to the data
 
@@ -63,7 +63,7 @@ def smooth(
         return self.smooth_fun(x, **self.method_args)
 
 def dct_smooth(
-        x:np.array, 
+        x:npt.NDArray, 
         order:int = 5
     ) -> Smoothed:
     """A DCT Smoother

From e3dbd03300a39a91ee224fef91d18b448382af51 Mon Sep 17 00:00:00 2001
From: JoFrhwld <JoFrhwld@gmail.com>
Date: Sun, 8 Feb 2026 17:35:05 -0500
Subject: [PATCH 3/9] update typing

---
 src/fasttrackpy/processors/heuristic.py | 16 ++++++++--------
 src/fasttrackpy/processors/outputs.py   | 12 ++++--------
 src/fasttrackpy/utils/safely.py         | 10 +++++-----
 3 files changed, 17 insertions(+), 21 deletions(-)

diff --git a/src/fasttrackpy/processors/heuristic.py b/src/fasttrackpy/processors/heuristic.py
index d8e216b..872463e 100644
--- a/src/fasttrackpy/processors/heuristic.py
+++ b/src/fasttrackpy/processors/heuristic.py
@@ -1,11 +1,12 @@
 from dataclasses import dataclass, field
 import numpy as np
+import numpy.typing as npt
 from collections.abc import Mapping
 from typing import TypeVar, TYPE_CHECKING, Literal, Annotated
+from collections.abc import Sequence
 if TYPE_CHECKING:
     from fasttrackpy import OneTrack
 
-TrackType = TypeVar("OneTrack")
 
 @dataclass
 class MinMaxHeuristic:
@@ -40,7 +41,7 @@ class MinMaxHeuristic:
     number: int = 1
     boundary: float|int|np.floating = 1200
 
-    def eval(self, track: TrackType):
+    def eval(self, track: OneTrack):
         """
         Evaluate whether or not the track passes the 
         heuristic
@@ -63,8 +64,7 @@ def eval(self, track: TrackType):
                 track.log_parameters[self.number-1,0]*
                 np.sqrt(2)
             )
-
-        if self.measure == "bandwidth":
+        else:
             mean_value = np.exp(
                 track.bandwidth_parameters[self.number-1, 0]
                 *np.sqrt(2)
@@ -98,8 +98,8 @@ class SpacingHeuristic:
         bottom_diff (float|int|np.floating):
             The spacing of the bottom formants
     """
-    top: list[int] = field(default_factory=lambda: [3])
-    bottom: list[int] = field(default_factory=lambda: [1,2])
+    top: Sequence[int]|npt.NDArray[np.int_] = field(default_factory=lambda: [3])
+    bottom: Sequence[int]|npt.NDArray[np.int_] = field(default_factory=lambda: [1,2])
     top_diff: float|int|np.floating = 2000
     bottom_diff: float|int|np.floating = 500
 
@@ -107,7 +107,7 @@ def __post_init__(self):
         self.top = np.array(self.top)
         self.bottom = np.array(self.bottom)
 
-    def eval(self, track:TrackType):
+    def eval(self, track:OneTrack):
         """
         Evaluate whether or not the track passes
         the heuriustic
@@ -123,7 +123,7 @@ def eval(self, track:TrackType):
         """
         nformants = track.n_formants
 
-        if nformants < self.top.max():
+        if nformants < np.array(self.top).max():
             return 0
         
         top_values = np.array([
diff --git a/src/fasttrackpy/processors/outputs.py b/src/fasttrackpy/processors/outputs.py
index 9acb8cb..c891c6a 100644
--- a/src/fasttrackpy/processors/outputs.py
+++ b/src/fasttrackpy/processors/outputs.py
@@ -149,8 +149,8 @@ def get_big_df(self, output):
 
 def write_data(
         candidates,
-        file: Path = None,
-        destination: Path = None,
+        file: Path|None = None,
+        destination: Path|None = None,
         which: str = "winner",
         output: str = "formants",
         separate: bool = False
@@ -435,12 +435,10 @@ def pickle_candidates(
             The file location to save the pickle file
             to.
     """
-    if type(file) is str:
-        file = Path(file)
     sys.setrecursionlimit(3000)
     #tmp_candidates = copy.deepcopy (candidates)
 
-    with file.open('wb') as f:
+    with Path(file).open('wb') as f:
         cloudpickle.dump(candidates, f)
 
 
@@ -460,10 +458,8 @@ def unpickle_candidates(
         (CandidateTracks):
             A CandidateTracks object.
     """
-    if type(file) is str:
-        file = Path(file)    
     sys.setrecursionlimit(3000)
-    with file.open('rb') as f:
+    with Path(file).open('rb') as f:
         candidates = cloudpickle.load(f)
 
     return candidates
diff --git a/src/fasttrackpy/utils/safely.py b/src/fasttrackpy/utils/safely.py
index cb61788..3b488eb 100644
--- a/src/fasttrackpy/utils/safely.py
+++ b/src/fasttrackpy/utils/safely.py
@@ -1,6 +1,6 @@
 import warnings
-from typing import Callable
-from typing import Sequence
+from typing import Any
+from collections.abc import Callable, Sequence
 
 
 def safely(
@@ -28,9 +28,9 @@ def safe_func(*args, **kwargs):
     return decorator
 
 def filter_nones(
-    filterer: Sequence,
-    to_filter: list[Sequence]
-)->list[Sequence]:
+    filterer: Sequence[Any],
+    to_filter: Sequence[Sequence[Any]]
+)->Sequence[Sequence[Any]]:
     """
     Filter lists based on the presence of None values.
 

From 2d516c5987fea16c38e00fa8b046e5cadf1f72d7 Mon Sep 17 00:00:00 2001
From: JoFrhwld <JoFrhwld@gmail.com>
Date: Sun, 8 Feb 2026 17:44:30 -0500
Subject: [PATCH 4/9] fix typing error

---
 src/fasttrackpy/processors/heuristic.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/fasttrackpy/processors/heuristic.py b/src/fasttrackpy/processors/heuristic.py
index 872463e..93fac17 100644
--- a/src/fasttrackpy/processors/heuristic.py
+++ b/src/fasttrackpy/processors/heuristic.py
@@ -41,7 +41,7 @@ class MinMaxHeuristic:
     number: int = 1
     boundary: float|int|np.floating = 1200
 
-    def eval(self, track: OneTrack):
+    def eval(self, track: "OneTrack"):
         """
         Evaluate whether or not the track passes the 
         heuristic
@@ -107,7 +107,7 @@ def __post_init__(self):
         self.top = np.array(self.top)
         self.bottom = np.array(self.bottom)
 
-    def eval(self, track:OneTrack):
+    def eval(self, track:"OneTrack"):
         """
         Evaluate whether or not the track passes
         the heuriustic

From 34c34f3d0a4b737e58710fa01c96fb12564e5df6 Mon Sep 17 00:00:00 2001
From: JoFrhwld <JoFrhwld@gmail.com>
Date: Sun, 8 Feb 2026 17:47:31 -0500
Subject: [PATCH 5/9] more typing updates

---
 src/fasttrackpy/cli.py                | 46 +++++++++++++--------------
 src/fasttrackpy/processors/outputs.py |  4 +--
 2 files changed, 25 insertions(+), 25 deletions(-)

diff --git a/src/fasttrackpy/cli.py b/src/fasttrackpy/cli.py
index 2212cb6..3607423 100644
--- a/src/fasttrackpy/cli.py
+++ b/src/fasttrackpy/cli.py
@@ -39,7 +39,7 @@
   "f3_f4_heuristic": F3_F4_Sep
 }
 
-DEFAULT_CONFIG = str(files("fasttrackpy").joinpath("resources", "config.yml"))
+DEFAULT_CONFIG = str(files("fasttrackpy").joinpath("resources").joinpath("config.yml"))
 
 logging.basicConfig(
     filename = "fasttrack.log",
@@ -300,17 +300,17 @@ def fasttrack():
 @smoother_options
 @heuristic_options
 def audio(
-        file: Union[str, Path] = None,
-        dir: Union[str,Path] = None,
-        output: Union[str, Path] = None,
-        dest: Union[str, Path] = None,
+        file: str|Path,
+        dir: str|Path,
+        output: str|Path,
+        dest: str|Path,
         which_output: str = "winner",
         data_output: str = "formants",
         smoother_method: str = "dct_smooth_regression",
         smoother_order: int = 5,
         loss_method: str = "lmse",
         xmin:float = 0,
-        xmax: float = None,
+        xmax: float|None = None,
         min_max_formant:float = 4000,
         max_max_formant:float = 7000,
         min_duration = 0.05,
@@ -454,13 +454,13 @@ def audio(
 @smoother_options
 @heuristic_options
 def audio_textgrid(
-        audio: Union[str, Path] = None,
-        textgrid: Union[str,Path] = None,
-        entry_classes: str = None,
-        target_tier: str = None,
-        target_labels: str = None,
-        output: Union[str, Path] = None,
-        dest: Union[str, Path] = None,
+        audio: str|Path,
+        textgrid: str|Path,
+        entry_classes: str,
+        target_tier: str,
+        target_labels: str,
+        output: str|Path,
+        dest: str|Path,
         which_output: str = "winner",
         data_output: str = "formants",
         smoother_method: str = "dct_smooth_regression",
@@ -533,12 +533,12 @@ def audio_textgrid(
         if k in heuristic_dict
     ]     
 
-    entry_classes = entry_classes.split("|")
+    entry_classes_list = entry_classes.split("|")
 
     all_candidates = process_audio_textgrid(
         audio_path=audio,
         textgrid_path=textgrid,
-        entry_classes=entry_classes,
+        entry_classes=entry_classes_list,
         target_tier=target_tier,
         target_labels=target_labels,
         min_duration=min_duration,
@@ -584,13 +584,13 @@ def audio_textgrid(
 @smoother_options
 @heuristic_options
 def corpus(
-        corpus: str|Path = None,
-        entry_classes: str = None,
-        target_tier: str = None,
-        target_labels: str = None,
-        output: str|Path = None,
+        corpus: str|Path,
+        entry_classes: str,
+        target_tier: str,
+        target_labels: str,
+        output: str|Path,
+        dest: str|Path,        
         separate_output: bool = False,
-        dest: str|Path = None,
         which_output: str = "winner",
         data_output: str = "formants",
         smoother_method: str = "dct_smooth_regression",
@@ -661,11 +661,11 @@ def corpus(
         if k in heuristic_dict
     ]         
 
-    entry_classes = entry_classes.split("|")
+    entry_classes_list = entry_classes.split("|")
 
     all_candidates = process_corpus(
         corpus_path = corpus,
-        entry_classes = entry_classes,
+        entry_classes = entry_classes_list,
         target_tier = target_tier,
         target_labels = target_labels,
         min_duration = min_duration,
diff --git a/src/fasttrackpy/processors/outputs.py b/src/fasttrackpy/processors/outputs.py
index c891c6a..e746fc3 100644
--- a/src/fasttrackpy/processors/outputs.py
+++ b/src/fasttrackpy/processors/outputs.py
@@ -149,8 +149,8 @@ def get_big_df(self, output):
 
 def write_data(
         candidates,
-        file: Path|None = None,
-        destination: Path|None = None,
+        file: str|Path|None = None,
+        destination: str|Path|None = None,
         which: str = "winner",
         output: str = "formants",
         separate: bool = False

From 7fc7995ad1d934326d22cbbe3d42f291aac2f320 Mon Sep 17 00:00:00 2001
From: JoFrhwld <JoFrhwld@gmail.com>
Date: Sun, 8 Feb 2026 17:56:58 -0500
Subject: [PATCH 6/9] finalizing typing

---
 src/fasttrackpy/processors/outputs.py |  4 ++--
 src/fasttrackpy/tracks.py             | 20 ++++++++++----------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/fasttrackpy/processors/outputs.py b/src/fasttrackpy/processors/outputs.py
index e746fc3..b7312b6 100644
--- a/src/fasttrackpy/processors/outputs.py
+++ b/src/fasttrackpy/processors/outputs.py
@@ -44,7 +44,7 @@ def add_metadata(self, out_df):
 
     return out_df
 
-def formant_to_dataframe(self):
+def formant_to_dataframe(self)->pl.DataFrame:
     """Return data as a data frame
 
     Returns:
@@ -135,7 +135,7 @@ def log_param_to_dataframe(self):
 
     return param_df
 
-def get_big_df(self, output):
+def get_big_df(self, output) -> pl.DataFrame:
         all_df = [x.to_df(output = output) for x in self.candidates]
         all_df = [
             x.with_columns(
diff --git a/src/fasttrackpy/tracks.py b/src/fasttrackpy/tracks.py
index b22e08e..51b2c10 100644
--- a/src/fasttrackpy/tracks.py
+++ b/src/fasttrackpy/tracks.py
@@ -142,9 +142,9 @@ def __init__(
             window_length: float = 0.025,
             time_step: float = 0.002,
             pre_emphasis_from: float = 50,
-            smoother: Smoother = Smoother(),
-            loss_fun: Loss = Loss(),
-            agg_fun: Agg = Agg(),
+            smoother: Smoother = Smoother(method="dct_smooth_regression"),
+            loss_fun: Loss = Loss(method = "lmse"),
+            agg_fun: Agg = Agg(method = "agg_sum"),
             heuristics: list[MinMaxHeuristic|SpacingHeuristic] = [],
         ):
         super().__init__(
@@ -171,9 +171,9 @@ def __init__(
         self._file_name = None
         self._id = None
         self._group = None
-        self._formant_df = None
-        self._param_df = None
-        self._log_param_df = None
+        self._formant_df = pl.DataFrame()
+        self._param_df = pl.DataFrame()
+        self._log_param_df = pl.DataFrame()
         self._interval = None
 
     def __repr__(self):
@@ -528,9 +528,9 @@ def __init__(
         self._id = None
         self._label = None
         self._group = None
-        self._formant_df = None
-        self._param_df = None
-        self._log_param_df = None
+        self._formant_df = pl.DataFrame()
+        self._param_df = pl.DataFrame()
+        self._log_param_df = pl.DataFrame()
         self._interval = None
 
         to_process = [
@@ -576,7 +576,7 @@ def __init__(
         self.intensity_smooth = self.smoother.smooth(self.intensity)
         self.intensity_log_smooth = self.smoother.smooth(np.log(self.intensity))        
 
-    def __getitem__(self, idx:int) -> OneTrack:
+    def __getitem__(self, idx:slice|int) -> OneTrack|Sequence[OneTrack]:
         return self.candidates[idx]
     
     def __len__(self) -> int:

From 5fd2ce9a533763f2138b881f58f89ba3d64122be Mon Sep 17 00:00:00 2001
From: JoFrhwld <JoFrhwld@gmail.com>
Date: Mon, 9 Feb 2026 09:24:31 -0500
Subject: [PATCH 7/9] fix dataframe checking

---
 src/fasttrackpy/tracks.py | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/fasttrackpy/tracks.py b/src/fasttrackpy/tracks.py
index e6f0ef7..80d1458 100644
--- a/src/fasttrackpy/tracks.py
+++ b/src/fasttrackpy/tracks.py
@@ -356,7 +356,7 @@ def to_df(
             (pl.DataFrame): A `polars.DataFrame`
         """
         if output == "formants"\
-              and not isinstance(self._formant_df, pl.DataFrame):
+              and self._formant_df.shape == (0, 0):
             df =  formant_to_dataframe(self)
             self._formant_df = df
             return df
@@ -364,7 +364,7 @@ def to_df(
             return self._formant_df
 
         if output == "param"\
-            and not isinstance(self._param_df, pl.DataFrame):
+            and self._param_df.shape == (0, 0):
             df =  param_to_dataframe(self)
             self._param_df = df
             return df
@@ -372,7 +372,7 @@ def to_df(
             return self._param_df
         
         if output == "log_param"\
-            and not isinstance(self._log_param_df, pl.DataFrame):
+            and self._log_param_df.shape == (0, 0):
             df = log_param_to_dataframe(self)
             self._log_param_df = df
             return df
@@ -691,7 +691,7 @@ def to_df(
                 return out_df
 
         if output == "formants"\
-            and not isinstance(self._formant_df, pl.DataFrame):
+            and self._formant_df.shape == (0, 0):
             big_df = get_big_df(self, output=output)
             self._formant_df = big_df
             return big_df
@@ -700,7 +700,7 @@ def to_df(
             return self._formant_df
 
         if output == "param"\
-            and not isinstance(self._param_df, pl.DataFrame):
+            and self._param_df.shape == (0, 0):
             big_df = get_big_df(self, output=output)
             self._param_df = big_df
             return big_df
@@ -709,7 +709,7 @@ def to_df(
             return self._param_df
         
         if output == "log_param"\
-            and not isinstance(self._log_param_df, pl.DataFrame):
+            and self._log_param_df.shape == (0, 0):
             big_df = get_big_df(self, output=output)
             self._log_param_df = big_df
             return big_df

From 69d2722518f993f178e45defe4e3b6ac494c9ecd Mon Sep 17 00:00:00 2001
From: JoFrhwld <JoFrhwld@gmail.com>
Date: Mon, 9 Feb 2026 09:24:44 -0500
Subject: [PATCH 8/9] error in test

---
 tests/test_patterns/test_audio_textgrid.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/test_patterns/test_audio_textgrid.py b/tests/test_patterns/test_audio_textgrid.py
index be4210b..7fafb41 100644
--- a/tests/test_patterns/test_audio_textgrid.py
+++ b/tests/test_patterns/test_audio_textgrid.py
@@ -69,7 +69,7 @@ def test_audio_tg2(self)    :
         candidates = process_audio_textgrid(
             audio_path=AUDIO_PATH,
             textgrid_path=TG_PATH,
-            entry_classes="SequenceInterval",
+            entry_classes=["SequenceInterval"],
             target_tier="phones",
             target_labels="AY"
         )

From 6d6888683693d6cbc85fde7a2cc017ceb3cee979 Mon Sep 17 00:00:00 2001
From: JoFrhwld <JoFrhwld@gmail.com>
Date: Mon, 9 Feb 2026 09:25:05 -0500
Subject: [PATCH 9/9] final typing update

---
 src/fasttrackpy/patterns/audio_textgrid.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/fasttrackpy/patterns/audio_textgrid.py b/src/fasttrackpy/patterns/audio_textgrid.py
index 0fcc872..5e25773 100644
--- a/src/fasttrackpy/patterns/audio_textgrid.py
+++ b/src/fasttrackpy/patterns/audio_textgrid.py
@@ -104,7 +104,7 @@ def process_audio_textgrid(
         smoother: Smoother = Smoother(),
         loss_fun: Loss = Loss(),
         agg_fun: Agg = Agg(),
-        heuristics: list[MinMaxHeuristic|SpacingHeuristic] = []     
+        heuristics: list[MinMaxHeuristic|SpacingHeuristic|None] = []     
 )->Sequence[CandidateTracks]:
     """Process an audio and TextGrid file together.