input: Write a python function to display the powers of 2 up to a given power.
  assert display_powers_of_2(3) == [1, 2, 4, 8]
  assert display_powers_of_2(5) == [1, 2, 4, 8, 16, 32]
  assert display_powers_of_2(0) == [1]
output: def display_powers_of_2(n):
      return [2**i for i in range(n + 1)]