code: def initialize_security_context(self):
          
          # Generate the NTLM Negotiate Request
          negotiate_token = self._negotiate(self.flags)
          challenge_token = yield negotiate_token
  
          # Generate the Authenticate Response
          authenticate_token = self._challenge_response(negotiate_token, challenge_token)
          yield authenticate_token
docs: Idiomatic Python implementation of initialize_security_context, implemented as a generator function using
          yield to both accept incoming and return outgoing authentication tokens
          :return: The response to be returned to the server