input: Write a function to remove all occurrences of a given item from a list. Return the modified list after all the specified items have been removed. If the list is empty, return an empty list.
  assert remove_item([1, 2, 3, 4, 2, 5, 2], 2)==[1, 3, 4, 5]
  assert remove_item([3, 5, 4, 1, 2], 4)==[3, 5, 1, 2]
  assert remove_item([4, 3, 1, 2], 5)==[4, 3, 1, 2]
  assert remove_item([], 2)==[]
output: def remove_item(lst, item):
      return [x for x in lst if x != item]