class_docstr: Set an environment variable for the context and unset it afterwards.
class_docstr_tok: ["Set","an","environment","variable","for","the","context","and","unset","it","afterwards","."]
code: def __exit__(self, exc_type, exc_value, exc_traceback):
      del os.environ[self.key]
      return True
  
imports: import os
  import socket
  import sys
  import threading
  from absl import flags
  import tensorflow
  from tensorflow_hub import resolver
label_desc: Use image node_id 3 for calling the EnvVariableContextManager obj's underlying member method code with example usage: obj.__exit__(exc_type, exc_value, exc_traceback) and returns: True