code: def clean_channel_worker_username(self):
          
          channel_worker_username = self.cleaned_data['channel_worker_username'].strip()
  
          try:
              User.objects.get(username=channel_worker_username)
          except User.DoesNotExist:
              raise ValidationError(
                  ValidationMessages.INVALID_CHANNEL_WORKER.format(
                      channel_worker_username=channel_worker_username
                  )
              )
  
          return channel_worker_username
docs: Clean enterprise channel worker user form field
  
          Returns:
              str: the cleaned value of channel user username for transmitting courses metadata.