new_contents: import abc
  
  class PluginTypeBase(object):
  
      __metaclass__ = abc.ABCMeta
  
      @staticmethod
      def is_valid_file(file):
          """ """
          return file.endswith('.py')
  
      def __init__(self ):
          pass
  
subject: add baseclass that can be used to derive proper PluginTypes from it