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 purchase (branch_id VARCHAR, year VARCHAR); CREATE TABLE branch (branch_id VARCHAR, city VARCHAR)
  ### Question:
  What is the sum of total pounds of purchase in year 2018 for all branches in London?
  ### Answer:
  SELECT SUM(total_pounds) FROM purchase AS T1 JOIN branch AS T2 ON T1.branch_id = T2.branch_id WHERE T2.city = 'London' AND T1.year = 2018