input: Write a function to prepend a given value to each element in a list.
  assert prepend_list(["one", "two", "three"], "STR-") == ["STR-one", "STR-two", "STR-three"]
  assert prepend_list(["apple", "banana", "cherry"], "fruit-") == ["fruit-apple", "fruit-banana", "fruit-cherry"]
  assert prepend_list(["car", "bike", "plane"], "vehicle-") == ["vehicle-car", "vehicle-bike", "vehicle-plane"]
output: def prepend_list(lst, prefix):
      return [prefix + item for item in lst]