code: def BytesSizer(field_number, is_repeated, is_packed):
    
  
    tag_size = _TagSize(field_number)
    local_VarintSize = _VarintSize
    local_len = len
    assert not is_packed
    if is_repeated:
      def RepeatedFieldSize(value):
        result = tag_size * len(value)
        for element in value:
          l = local_len(element)
          result += local_VarintSize(l) + l
        return result
      return RepeatedFieldSize
    else:
      def FieldSize(value):
        l = local_len(value)
        return tag_size + local_VarintSize(l) + l
      return FieldSize
docs: Returns a sizer for a bytes field.