text: Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
  ### Context:
  CREATE TABLE table_name_3 (cars_per_set INTEGER, operator VARCHAR)
  ### Question:
  Tell me the sum of cars per set for operator of london midland
  ### Answer:
  SELECT SUM(cars_per_set) FROM table_name_3 WHERE operator = "london midland"