def add_vnic_template(self, vlan_id, ucsm_ip, vnic_template, physnet):
        """Adds an entry for a vlan_id on a SP template to the table."""
        if not self.get_vnic_template_vlan_entry(vlan_id, vnic_template,
            ucsm_ip, physnet):
            vnic_t = ucsm_model.VnicTemplate(vlan_id=vlan_id,
                                             vnic_template=vnic_template,
                                             device_id=ucsm_ip,
                                             physnet=physnet,
                                             updated_on_ucs=False)
            with self.session.begin(subtransactions=True):
                self.session.add(vnic_t)
            return vnic_t