code: def send_text_message(self, recipient_id, message, notification_type=NotificationType.regular):
          
          return self.send_message(recipient_id, {
              'text': message
          }, notification_type)
docs: Send text messages to the specified recipient.
          https://developers.facebook.com/docs/messenger-platform/send-api-reference/text-message
          Input:
              recipient_id: recipient id to send to
              message: message to send
          Output:
              Response from API as <dict>