docs: def send(self, id_, text, identities, context=None):
          """
          Send messages when using RapidSMS 0.14.0 or later.
  
          We can send multiple messages in one Tropo program, so we do
          that.
  
          :param id_: Unused, included for compatibility with RapidSMS.
          :param string text: The message text to send.
          :param identities: A list of identities to send the message to
              (a list of strings)
          :param context: Unused, included for compatibility with RapidSMS.
          """
  
          # Build our program
          from_ = self.config['number'].replace('-', '')
          commands = []
          for identity in identities:
              # We'll include a 'message' command for each recipient.
              # The Tropo doc explicitly says that while passing a list
              # of destination numbers is not a syntax error, only the
              # first number on the list will get sent the message. So
              # we have to send each one as a separate `message` command.
              commands.append(
                  {
                      'message': {
                          'say': {'value': text},
                          'to': identity,
                          'from': from_,
                          'channel': 'TEXT',
                          'network': 'SMS'
                      }
                  }
              )
              program = {
                  'tropo': commands,
              }
          self.execute_tropo_program(program)