input: Write a function to generate a staircase pattern of height 'n' using Python. If 'n' is an integer, the function should print the staircase using spaces and '#' symbols. If 'n' is 0 or negative, the function should not print anything.
  
  assert staircase(5)==None
  assert staircase(3)==None
  assert staircase(0)==None
  assert staircase(-1)==None
output: def staircase(n):
      if n > 0:
          for i in range(1, n + 1):
              print(' ' * (n - i) + '#' * i)