input: Write a function to generate a staircase of height `n`, where `n` is an integer. The function should print a staircase pattern where each step is represented by the '#' character, and the steps ascend from left to right.
  assert staircase(5)
  # The output should be:
  #     #
  #    ##
  #   ###
  #  ####
  # #####
output: def staircase(n):
      for i in range(1, n + 1):
          print(' ' * (n - i) + '#' * i)