class_docstr: Mapping where default values are zero
class_docstr_tok: ["Mapping","where","default","values","are","zero"]
code: def __missing__(self, key):
      return 0
  
imports: from functools import update_wrapper, partial
  from klepto.archives import cache
  from klepto.keymaps import hashmap
  from klepto.tools import CacheInfo
  from klepto.rounding import deep_round, simple_round
  from ._inspect import _keygen
label_desc: Use image node_id 1 for calling the Counter obj's underlying member method code with example usage: obj.__missing__(key) and returns: int