It is imprecise error message. `.render()` method is given 2 arguments (self and `update_value`), 2 keyword arguments that are also used by `__call__` itself (thus they are in method declaration and not in `kwargs`) and whatever other keyword arguments supplied by user or segment (as effect of attribute set by `requires_segment_info` decorator) configuration. There is no need to make these two keyword arguments be specified in the method declaration.