def _proxy(self):
        """
        Generate an instance context for the instance, the context is capable of
        performing various actions.  All instance actions are proxied to the context

        :returns: DomainContext for this DomainInstance
        :rtype: twilio.rest.api.v2010.account.sip.domain.DomainContext
        """
        if self._context is None:
            self._context = DomainContext(
                self._version,
                account_sid=self._solution['account_sid'],
                sid=self._solution['sid'],
            )
        return self._context
Generate an instance context for the instance, the context is capable of
        performing various actions.  All instance actions are proxied to the context

        :returns: DomainContext for this DomainInstance
        :rtype: twilio.rest.api.v2010.account.sip.domain.DomainContext