code: def __exit__(self, *exc):
      self.unlock()
      return None
  
file_path: mpi4py/demo/nxtval/nxtval-scalable.py
imports: from mpi4py import MPI
  import struct
label_desc: Use image node_id 3 for calling the Mutex obj's underlying member method code with example usage: obj.__exit__() and returns: None