fn ensure_signatures_on_valid_method(
fn_type: &FnType,
signature: Option<&KeywordAttribute<signature, Signature>>,
text_signature: Option<&KeywordAttribute<text_signature, TextSignatureAttributeValue>>,
) -> Result<()>
fn ensure_signatures_on_valid_method(
fn_type: &FnType,
signature: Option<&KeywordAttribute<signature, Signature>>,
text_signature: Option<&KeywordAttribute<text_signature, TextSignatureAttributeValue>>,
) -> Result<()>