input: Write a function to generate a staircase of height `n`, where `n` is an integer. The staircase should be right-aligned and constructed using the `#` symbol. If `n` is 0, the function should not print anything.
  assert staircase(5)==None
  assert staircase(3)==None
  assert staircase(0)==None
output: def staircase(n):
      for i in range(1, n + 1):
          print(' ' * (n - i) + '#' * i)