def command_update(self):
        """Update package lists repositories
        """
        if len(self.args) == 1 and self.args[0] == "update":
            Update().repository(only="")
        elif (len(self.args) == 2 and self.args[0] == "update" and
                self.args[1].startswith("--only=")):
            repos = self.args[1].split("=")[-1].split(",")
            for rp in repos:
                if rp not in self.meta.repositories:
                    repos.remove(rp)
            Update().repository(repos)
        else:
            usage("")
Update package lists repositories