input: Write a python function to add items to a list and search for a query within that list.
  assert test_stringlist(['apple', 'banana', 'cherry'], 'banana')==True
  assert test_stringlist(['apple', 'banana', 'cherry'], 'grape')==False
  assert test_stringlist([], 'apple')==False
output: def test_stringlist(items, query):
      items.append(query)
      return query in items