code: def _FixedSizer(value_size):
    
  
    def SpecificSizer(field_number, is_repeated, is_packed):
      tag_size = _TagSize(field_number)
      if is_packed:
        local_VarintSize = _VarintSize
        def PackedFieldSize(value):
          result = len(value) * value_size
          return result + local_VarintSize(result) + tag_size
        return PackedFieldSize
      elif is_repeated:
        element_size = value_size + tag_size
        def RepeatedFieldSize(value):
          return len(value) * element_size
        return RepeatedFieldSize
      else:
        field_size = value_size + tag_size
        def FieldSize(value):
          return field_size
        return FieldSize
  
    return SpecificSizer
docs: Like _SimpleSizer except for a fixed-size field.  The input is the size
    of one value.