human
I wrote the below code

    def SpecificSizer(field_number, is_repeated, is_packed):
        tag_size = _TagSize(field_number)
        if is_packed:
            local_VarintSize = _VarintSize
            def PackedFieldSize(value):
                result = 0
                for element in value:
                    result += compute_value_size(element)
                return ((result + local_VarintSize(result)) + tag_size)
            return PackedFieldSize
        elif is_repeated:
            def RepeatedFieldSize(value):
                result = (tag_size * len(value))
                for element in value:
                    result += compute_value_size(element)
                return result
            return RepeatedFieldSize
        else:
            def FieldSize(value):
                return (tag_size + compute_value_size(value))
            return FieldSize
    return SpecificSizer

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

def _SimpleSizer(compute_value_size):