input: Write a function to print the following pattern: a triangle of asterisks (*) where the top part has ascending height and the bottom part has descending height. The top part includes 5 lines, and the bottom part also includes 5 lines.
  
  assert print_pattern() == None
  
  The function should print the following pattern as output:
  *
  **
  ***
  ****
  *****
  ****
  ***
  **
  *
output: def print_pattern():
      for i in range(1, 6):
          print('*' * i)
      for i in range(4, 0, -1):
          print('*' * i)