input: Write a function to make the provided Python code more efficient by using a list comprehension.
  assert efficient_code([1, 2, 3, 4])==[3, 4]
  assert efficient_code([5, 1, 4, 2])==[5, 4]
  assert efficient_code([3, 4, 5, 6])==[3, 4, 5, 6]
  assert efficient_code([])==[]
  assert efficient_code([2, 2, 2, 2])==[]
output: def efficient_code(lst):
      return [x for x in lst if x > 2]