input: Write a function to print a staircase of height 'n', where n is an integer. If 'n' is 0, the function should print nothing.
  def staircase(n):
      if n == 0:
          return
      for i in range(n):
          print(" " * (n - i - 1) + "#" * (i + 1))
  
  # Test cases
  assert staircase(5) == None
  assert staircase(0) == None
  assert staircase(3) == None
output: def staircase(n):
      if n == 0:
          return
      for i in range(n):
          print(" " * (n - i - 1) + "#" * (i + 1))