'Creates a customized copy of the Signature.
Pass \'parameters\' and/or \'return_annotation\' arguments
to override them in the new copy.'

def replace(self, parameters=_void, return_annotation=_void):

    if (parameters is _void):
        parameters = self.parameters.values()
    if (return_annotation is _void):
        return_annotation = self._return_annotation
    return type(self)(parameters, return_annotation=return_annotation)
