code: def getTypes(cls):
      
  
      for attrName in dir(cls):
        attrValue = getattr(cls, attrName)
        if (isinstance(attrValue, type)):
          yield attrName
docs: Get sequence of acceptable model types.  Iterates through class
      attributes and separates the user-defined enumerations from the default
      attributes implicit to Python classes. i.e. this function returns the names
      of the attributes explicitly defined above.