code: def unique(self, token_list_x, token_list_y):
          '''
          Remove duplicated elements.
          
          Args:
              token_list_x:    [token, token, token, ...]
              token_list_y:    [token, token, token, ...]
  
          Returns:
              Tuple(token_list_x, token_list_y)
          '''
          x = set(list(token_list_x))
          y = set(list(token_list_y))
          return (x, yf unique(self, token_list_x, token_list_y):
          '''
          Remove duplicated elements.
          
          Args:
              token_list_x:    [token, token, token, ...]
              token_list_y:    [token, token, token, ...]
  
          Returns:
              Tuple(token_list_x, token_list_y)
          '''
          x = set(list(token_list_x))
          y = set(list(token_list_y))
          return (x, y)
docs: Remove duplicated elements.
          
          Args:
              token_list_x:    [token, token, token, ...]
              token_list_y:    [token, token, token, ...]
  
          Returns:
              Tuple(token_list_x, token_list_y)