code: def _validate_action_parameters(func, params):
      
      if params is not None:
          # Verify field name is valid
          valid_fields = [getattr(fields, f) for f in dir(fields) \
                  if f.startswith("FIELD_")]
          for param in params:
              param_name, field_type = param['name'], param['fieldType']
              if param_name not in func.__code__.co_varnames:
                  raise AssertionError("Unknown parameter name {0} specified for"\
                          " action {1}".format(
                          param_name, func.__name__))
  
              if field_type not in valid_fields:
                  raise AssertionError("Unknown field type {0} specified for"\
                          " action {1} param {2}".format(
                          field_type, func.__name__, param_name))
docs: Verifies that the parameters specified are actual parameters for the
      function `func`, and that the field types are FIELD_* types in fields.