Convert ZNB functions to methods.

docs/changes/newsfragments/7715.improved_driver

@@ -0,0 +1 @@
+In the Rohde Schwarz ZNB drivers QCoDeS functions have been converted to regular methods. This ensures that methods are type checked and can be discovered by IDEs.

src/qcodes/instrument_drivers/rohde_schwarz/ZNB.py

@@ -735,12 +735,13 @@ def __init__(
         using the other channel settings and zero delay
         """
 
-        self.add_function(
-            "set_electrical_delay_auto", call_cmd=f"SENS{n}:CORR:EDEL:AUTO ONCE"
-        )
-        self.add_function(
-            "autoscale",
-            call_cmd=f"DISPlay:TRACe1:Y:SCALe:AUTO ONCE, {self._tracename}",
+    def set_electrical_delay_auto(self) -> None:
+        n = self._instrument_channel
+        self.root_instrument.write(f"SENS{n}:CORR:EDEL:AUTO ONCE")
+
+    def autoscale(self) -> None:
+        self.root_instrument.write(
+            f"DISPlay:TRACe1:Y:SCALe:AUTO ONCE, {self._tracename}"
         )
 
     def _get_format(self, tracename: str) -> str:
@@ -1146,27 +1147,6 @@ def __init__(
         For external reference: check frequency and level of the supplied
         reference signal.
         """
-
-        self.add_function("reset", call_cmd="*RST")
-        self.add_function("tooltip_on", call_cmd="SYST:ERR:DISP ON")
-        self.add_function("tooltip_off", call_cmd="SYST:ERR:DISP OFF")
-        self.add_function("cont_meas_on", call_cmd="INIT:CONT:ALL ON")
-        self.add_function("cont_meas_off", call_cmd="INIT:CONT:ALL OFF")
-        self.add_function("update_display_once", call_cmd="SYST:DISP:UPD ONCE")
-        self.add_function("update_display_on", call_cmd="SYST:DISP:UPD ON")
-        self.add_function("update_display_off", call_cmd="SYST:DISP:UPD OFF")
-        self.add_function(
-            "display_sij_split",
-            call_cmd=f"DISP:LAY GRID;:DISP:LAY:GRID {num_ports},{num_ports}",
-        )
-        self.add_function(
-            "display_single_window", call_cmd="DISP:LAY GRID;:DISP:LAY:GRID 1,1"
-        )
-        self.add_function(
-            "display_dual_window", call_cmd="DISP:LAY GRID;:DISP:LAY:GRID 2,1"
-        )
-        self.add_function("rf_off", call_cmd="OUTP1 OFF")
-        self.add_function("rf_on", call_cmd="OUTP1 ON")
         if reset_channels:
             self.reset()
             self.clear_channels()
@@ -1228,3 +1208,46 @@ def clear_channels(self) -> None:
         for submodule in self.submodules.values():
             if isinstance(submodule, ChannelList):
                 submodule.clear()
+
+    def reset(self) -> None:
+        """
+        Reset the instrument to default settings.
+        """
+        self.write("*RST")
+
+    def update_display_on(self) -> None:
+        self.write("SYST:DISP:UPD ON")
+
+    def tooltip_on(self) -> None:
+        self.write("SYST:ERR:DISP ON")
+
+    def tooltip_off(self) -> None:
+        self.write("SYST:ERR:DISP OFF")
+
+    def cont_meas_on(self) -> None:
+        self.write("INIT:CONT:ALL ON")
+
+    def cont_meas_off(self) -> None:
+        self.write("INIT:CONT:ALL OFF")
+
+    def update_display_once(self) -> None:
+        self.write("SYST:DISP:UPD ONCE")
+
+    def update_display_off(self) -> None:
+        self.write("SYST:DISP:UPD OFF")
+
+    def display_sij_split(self) -> None:
+        num_ports = self.num_ports.cache.get()
+        self.write(f"DISP:LAY GRID;:DISP:LAY:GRID {num_ports},{num_ports}")
+
+    def display_single_window(self) -> None:
+        self.write("DISP:LAY GRID;:DISP:LAY:GRID 1,1")
+
+    def display_dual_window(self) -> None:
+        self.write("DISP:LAY GRID;:DISP:LAY:GRID 2,1")
+
+    def rf_off(self) -> None:
+        self.write("OUTP1 OFF")
+
+    def rf_on(self) -> None:
+        self.write("OUTP1 ON")