code: def get_param_descriptor(mcs,param_name):
          
          classes = classlist(mcs)
          for c in classes[::-1]:
              attribute = c.__dict__.get(param_name)
              if isinstance(attribute,Parameter):
                  return attribute,c
          return None,None
docs: Goes up the class hierarchy (starting from the current class)
          looking for a Parameter class attribute param_name. As soon as
          one is found as a class attribute, that Parameter is returned
          along with the class in which it is declared.