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_17 (year INTEGER, engine VARCHAR, entrant VARCHAR)
  ### Question:
  What is the average Year when there was a cosworth straight-4 engine, and the Entrant was ron harris / team lotus?
  ### Answer:
  SELECT AVG(year) FROM table_name_17 WHERE engine = "cosworth straight-4" AND entrant = "ron harris / team lotus"