class_docstr: Context manager for defining _shell as 'fake' - used for tests.
class_docstr_tok: ["Context","manager","for","defining","_shell","as","'fake","'","-","used","for","tests","."]
code: def __enter__(self):
      self._saved = _shell
      globals()["_shell"] = "fake"
  
imports: import logging
  import logging.config
  import os
  import sys
  from guild import ansi_util
label_desc: Use image node_id 1 for calling the _FakeShell obj's underlying member method code with example usage: obj.__enter__() without return types