krausening-python: If no default value is passed in, an exception is thrown

[ewilkins-csi]

The defaultvalue argument is supposed to be optional in getProperty, but if it's not provided I get the following error:

Traceback (most recent call last):
  File "/opt/spark/jobs/pipelines/usgs-api-data/usgs_api_data_driver.py", line 31, in <module>
    ingest = Ingest().execute_step()
  File "/opt/spark/.local/lib/python3.9/site-packages/usgs_api_data/generated/step/ingest_base.py", line 56, in execute_step
    outbound = self.execute_step_impl()
  File "/opt/spark/.local/lib/python3.9/site-packages/usgs_api_data/step/ingest.py", line 44, in execute_step_impl
    self.config.query_additional(),
  File "/opt/spark/.local/lib/python3.9/site-packages/usgs_api_data/config/usgs_config.py", line 122, in query_additional
    raw_values = self.properties.getProperty("query.additional")
  File "/opt/spark/.local/lib/python3.9/site-packages/krausening/properties/property_manager.py", line 182, in getProperty
    return os.path.expandvars(defaultValue)
  File "/usr/local/lib/python3.9/posixpath.py", line 284, in expandvars
    path = os.fspath(path)
TypeError: expected str, bytes or os.PathLike object, not NoneType

This is the calling code:

import os
from datetime import date, datetime
from krausening.properties import PropertyManager
from krausening.logging import LogManager

class UsgsConfig:
    def __init__(self):
        self.properties = PropertyManager.get_instance().get_properties(
            "usgs.properties"
        )


    def query_additional(self) -> {str, str}:
        raw_values = self.properties.getProperty("query.additional")
        additional = {}
        if raw_values is not None:
            for pair in raw_values.split("&"):
                key, value = pair.split("=")
                additional[key] = value
        return additional