old_contents: from base import BaseMatcher
  
  
  class GreetingMatcher(BaseMatcher):
  
      name = 'greeter'
      greetings = [
          'all: morning',
          'all: howdy',
          'all: greetings',
          'all: hello',
          'all: hey',
          'all: hi',
          ''
      ]
  
      def respond(self, message, user=None):
          if message.lower() in self.greetings:
              message = "hey"
              if user:
                  message = user + ": " + message
              self.speak(message)
  
  
new_contents: from base import BaseMatcher
  
  
  class GreetingMatcher(BaseMatcher):
  
      name = 'greeter'
      greetings = [
          'all: morning',
          'all: howdy',
          'all: greetings',
          'all: hello',
          'all: hey',
          'all: hi',
          ''
      ]
  
      def respond(self, message, user=None):
          if message.lower() in self.greetings:
              if user:
                  message = user + ": hey"
                  self.speak(message)
  
          if message.lower() == 'all: back':
              if user:
                  message = user + ": welcome back"
                  self.speak(message)
  
subject: Add welcome back greeting