human
Here's a good function header given the following:
I wrote the below code

    assert (not is_comparison(op))
    @with_name(method_name_for_op(op, commute=True))
    @coerce_numbers_to_my_dtype
    def reflected_binary_operator(self, other):
        if isinstance(self, NumericalExpression):
            (self_expr, other_expr, new_inputs) = self.build_binary_op(op, other)
            return NumExprFactor('({left})    {op}    ({right})'.format(left=other_expr, right=self_expr, op=op), new_inputs, dtype=binop_return_dtype(op, other.dtype, self.dtype))
        elif isinstance(other, Number):
            return NumExprFactor('{constant}    {op}    x_0'.format(op=op, constant=other), binds=(self,), dtype=binop_return_dtype(op, other.dtype, self.dtype))
        raise BadBinaryOperator(op, other, self)
    return reflected_binary_operator

What's a good function header?
assistant
#Here's a good function header.

def reflected_binary_operator(op):