input: Write a python function to remove all occurrences of a specified item from a list.
  assert remove_item([1, 2, 1, 3, 4, 1], 1) == [2, 3, 4]
  assert remove_item([5, 6, 7, 8, 7, 9, 7], 7) == [5, 6, 8, 9]
  assert remove_item([10, 20, 30, 40, 50], 20) == [10, 30, 40, 50]
output: def remove_item(lst, item):
      return [x for x in lst if x != item]