Error if YAML file is empty

[PyEVENG - login] ...
https://172.16.194.239 admin eve
Traceback (most recent call last):
  File "./eveng-api.py", line 455, in <module>
    main()
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "./eveng-api.py", line 282, in main
    validateYamlFileForPyEVENG(api, ymlF, vmInfo)
  File "/Volumes/Data/gitlab/python-eveng-api/tests/EveYAMLValidate.py", line 183, in validateYamlFileForPyEVENG
    if check_if_keys_are_in_yaml_file(yaml_content) is False:
  File "/Volumes/Data/gitlab/python-eveng-api/tests/EveYAMLValidate.py", line 592, in check_if_keys_are_in_yaml_file
    all_keys = yaml_content.keys()
AttributeError: 'NoneType' object has no attribute 'keys'