Actually, that specific solution (using a helper method) will fail because there may be unhashable params (due to unhashable default values or annotations) among the keyword-only arguments, so it may not be possible to build a frozenset (rather, one should compare the {param.name: param if param.kind == KEYWORD_ONLY} dict).  The frozenset approach still works for computing the hash as this requires all params to be hashable anyways.