code: def __enter__(self) -> "MockTokenStore":
      self._exp_calls: List[Any] = []
      self._retvals: List[Any] = []
      self._ncalls = 0
      self._real = authentication.TokenStore
      authentication.TokenStore = self  # type: ignore
      return self
  
imports: import contextlib
  import os
  from typing import Any, Iterator, List, Optional, cast
  import responses
  from responses import registries
  import determined
  from determined.common.api import authentication
label_desc: Use image node_id 3 for calling the MockTokenStore obj's underlying member method code with example usage: obj.__enter__() and returns: self