def application_name(self):
        """
        The name of the remote application for this relation, or ``None``.

        This is equivalent to::

            relation.units[0].unit_name.split('/')[0]
        """
        if self._application_name is None and self.units:
            self._application_name = self.units[0].unit_name.split('/')[0]
        return self._application_name
The name of the remote application for this relation, or ``None``.

        This is equivalent to::

            relation.units[0].unit_name.split('/')[0]