input: Write a function to remove an item from a list if it exists and handle the case when the item is not present.
  assert remove_item([1, 2, 3, 4, 5], 3) == [1, 2, 4, 5]
  assert remove_item([1, 2, 3, 4, 5], 6) == [1, 2, 3, 4, 5]
  assert remove_item(['a', 'b', 'c', 'd'], 'b') == ['a', 'c', 'd']
  assert remove_item(['a', 'b', 'c', 'd'], 'e') == ['a', 'b', 'c', 'd']
output: def remove_item(lst, item):
      if item in lst:
          lst.remove(item)
      return lst