human
Complete the below
def GroupSizer(field_number, is_repeated, is_packed):

    ''''Returns a sizer for a group field.'
    '''
assistant
#Here is the Python code you requested.
    tag_size = (_TagSize(field_number) * 2)
    assert (not is_packed)
    if is_repeated:
        def RepeatedFieldSize(value):
            result = (tag_size * len(value))
            for element in value:
                result += element.ByteSize()
            return result
        return RepeatedFieldSize
    else:
        def FieldSize(value):
            return (tag_size + value.ByteSize())
        return FieldSize