code: def _discover_params(cls):
          
  
          try:
              return cls.filters
          except AttributeError:
              filters = {}
              for param_class_name in dir(cls):
                  param_class = getattr(cls, param_class_name)
                  if hasattr(param_class, 'kwarg'):
                      filters[param_class.kwarg] = param_class
                      filters[param_class.param_name] = param_class
              cls.filters = filters
          return cls.filters
docs: Returns a dict where filter keyword is key, and class is value.
          To handle param alias (maxRecords or max_records), both versions are
          added.