code: def auth_user(self, username, password):
          
  
          response = self._post(self.rest_url + "/authentication",
                                data=json.dumps({"value": password}),
                                params={"username": username})
  
          # If authentication failed for any reason return None
          if not response.ok:
              return None
  
          # ...otherwise return a dictionary of user attributes
          return response.json()
docs: Authenticate a user account against the Crowd server.
  
          Attempts to authenticate the user against the Crowd server.
  
          Args:
              username: The account username.
  
              password: The account password.
  
          Returns:
              dict:
                  A dict mapping of user attributes if the application
                  authentication was successful. See the Crowd documentation
                  for the authoritative list of attributes.
  
              None: If authentication failed.