input: Write a function to remove a specified item from a list.
  assert remove_item([1, 2, 3, 4, 5], 3) == [1, 2, 4, 5]
  assert remove_item([10, 20, 30, 40, 50], 20) == [10, 30, 40, 50]
  assert remove_item(['apple', 'banana', 'cherry'], 'banana') == ['apple', 'cherry']
output: def remove_item(lst, item):
      return [x for x in lst if x != item]