code: def from_json(cls, data):
          
          user = cls()
  
          user.user_id = data['userId']
          user.username = data['username']
          user.auth_system = data['authSystem']
          user.roles = data['roles']
  
          return user
docs: Return object based on JSON / dict input
  
          Args:
              data (dict): Dictionary containing a serialized User object
  
          Returns:
              :obj:`User`: User object representing the data