title: Pycharm Python Unused Imports For Subclasses Imports Although They Are Implicitly Used
body: <p>In my following code, I have a base class in python and a few sub classes that inherits from this class.
  Every sub class has a convert function, and a should_convert function.
  What I am trying to do is iterate through all sub classes, and if the sub class should convert, then perform convert later on.
  Code looks something like this</p>
  <pre><code>    from {file path to converter a} import ConverterA
      from {file path to converter b} import ConverterB
      all_converters = [converter(input_path, server_version) for converter in AbstractConverter.__subclasses__()]
      relevant_converters = [converter for converter in all_converters if converter.should_convert()]
      for converter in relevant_converters:
          converter.convert()
  </code></pre>
  <p>So in order to find sub classes, I had to import them (else it would not recognise the sub classes)</p>
  <p>But Pycharm says those imports are not used (where it is used implicitly in sub_classes method).
  Any help on how to make imports marked as used? or maybe this approach to the code is not a good practice and other approach should be used?</p>
  <p>Thanks.</p>