old_contents: # -*- coding: utf-8 -*-
  
  import time
  from watchdog.observers import Observer
  from watchdog.events import LoggingEventHandler, PatternMatchingEventHandler
  
  
  class FileWatcher(object):
  
      def __init__(self, runner):
          self.runner = runner
  
      def wait_for_events(self):
          event_handler = _RunnerEventHandler(self.runner)
          observer = Observer()
          observer.schedule(event_handler, path='.', recursive=True)
          observer.start()
          try:
              while True:
                  time.sleep(5)
          except KeyboardInterrupt:
              observer.stop()
          observer.join()
  
  
  class _RunnerEventHandler(PatternMatchingEventHandler):
  
      def __init__(self, runner):
          super(_RunnerEventHandler, self).__init__(patterns=['*.py'])
          self.runner = runner
  
      def on_modified(self, event):
          self.runner.run()
  
      def on_deleted(self, event):
          self.runner.run()
  
new_contents: # -*- coding: utf-8 -*-
  
  from mamba.infrastructure import is_python3
  
  if not is_python3():
      import time
      from watchdog.observers import Observer
      from watchdog.events import LoggingEventHandler, PatternMatchingEventHandler
  
  
      class FileWatcher(object):
  
          def __init__(self, runner):
              self.runner = runner
  
          def wait_for_events(self):
              event_handler = _RunnerEventHandler(self.runner)
              observer = Observer()
              observer.schedule(event_handler, path='.', recursive=True)
              observer.start()
              try:
                  while True:
                      time.sleep(5)
              except KeyboardInterrupt:
                  observer.stop()
              observer.join()
  
  
      class _RunnerEventHandler(PatternMatchingEventHandler):
  
          def __init__(self, runner):
              super(_RunnerEventHandler, self).__init__(patterns=['*.py'])
              self.runner = runner
  
          def on_modified(self, event):
              self.runner.run()
  
          def on_deleted(self, event):
              self.runner.run()
  
subject: Fix the build