CREATE TABLE "list_of_street_railways_in_canada" (
  "name_of_system" text,
  "location" text,
  "traction_type" text,
  "date_from" text,
  "date_to" text
);

Question: What is the date (to) associated wiht a traction type of electric and the Yarmouth Light and Power Company system?
SQL: SELECT "date_to" FROM "list_of_street_railways_in_canada" WHERE "traction_type"='electric' AND "name_of_system"='yarmouth light and power company';