class_docstr: Simple, type-checked, dict-like container for with submessage values.
class_docstr_tok: ["Simple",",","type-checked",",","dict-like","container","for","with","submessage","values","."]
code: def __setitem__(self, key, value):
      raise ValueError(
          "May not set values directly, call my_map[key].foo = 5"
      )
  
imports: import collections
  import sys
label_desc: Use image node_id 6 for calling the MessageMap obj's underlying member method code with example usage: obj.__setitem__(key, value) without return types