input: Write a function to create an infinite counter that increments every second, and stops when interrupted by the user (KeyboardInterrupt).
  assert infinite_counter() == 'Goodbye!'
output: import time
  
  def infinite_counter():
      try:
          count = 0
          while True:
              print(count)
              count += 1
              time.sleep(1)
      except KeyboardInterrupt:
          return 'Goodbye!'