code: def __repr__(self):
      return f"C({self.k}, {self.i})"
  
imports: from __future__ import annotations
  import heapq
  import operator
  import pickle
  import random
  from collections.abc import Mapping
  import pytest
  from distributed.collections import LRU, HeapSet, sum_mappings
label_desc: Use image node_id 4 for calling the C obj's underlying member method code with example usage: obj.__repr__() and returns: str, self, str, self, str