Lists the existing ipsets.

        If setname is given, only lists this ipset.

        The resulting command looks like one of the following:
        
        * ``ipset list``
        * ``ipset list ellis_blacklist4``

async def list(self, setname=None):
        """
        Lists the existing ipsets.

        If setname is given, only lists this ipset.

        The resulting command looks like one of the following:
        
        * ``ipset list``
        * ``ipset list ellis_blacklist4``

        """
        args = ['list']

        if setname is not None:
            args.append(setname)

        return await self.start(__class__.CMD, *args)