input: Write a function to print a staircase of height 'n', where n is an integer. If n is greater than zero, the function should print 'n' rows, where each row starts with spaces followed by a '#' character. If n is zero or negative, the function should print nothing.
  
  def staircase(n): 
      if n > 0:
          for i in range(0, n): 
              for j in range(0, n - i - 1): 
                  print(end=" ") 
              for j in range(0, i + 1): 
                  print("#", end="") 
              print("\r") 
    
  assert staircase(5)==None
  assert staircase(3)==None
  assert staircase(0)==None
  assert staircase(-1)==None
  assert staircase(1)==None
output: def staircase(n): 
      if n > 0:
          for i in range(0, n): 
              for j in range(0, n - i - 1): 
                  print(end=" ") 
              for j in range(0, i + 1): 
                  print("#", end="") 
              print()