query_async is not working

[DiarmaidEverycs]

PyOrient Version: 1.5.5
OrientDB version: 2.2.35

I am trying to asynchronously get records from the database, using the get_query_async() function. I have a very simple example:

`class testGraph():
def add_to_graphl(self, record):
print("We succeeded in getting a record")

def get_from_database(self, client):
""" client --> database connection returned by pyorient.OrientDB(database, port)
query = """select from "
limit = -1
fetchplan = "@*:-2"
client.query_async(query, limit, fetchplan, self.add_to_graph)
`

This is failing with:

pyorient.exceptions.PyOrientBadMethodCallException: <bound method testGraph.add_to_graph of <main.testGraph object at 0x7f5a0e2d3390>> is not a callable function