class_docstr: An abstract base class for context managers.
class_docstr_tok: ["An","abstract","base","class","for","context","managers","."]
docstr: Return `self` upon entering the runtime context.
docstr_tok: ["Return","`","self","`","upon","entering","the","runtime","context","."]
code: def __enter__(self):
      """Return `self` upon entering the runtime context."""
      return self
  
imports: import abc
  import sys
  import warnings
  from collections import deque
  from functools import wraps
label_desc: Use image node_id 1 for calling the AbstractContextManager obj's underlying member method code with example usage: obj.__enter__() and returns: self