def show_hbonds(self):
        """Visualizes hydrogen bonds."""
        hbonds = self.plcomplex.hbonds
        for group in [['HBondDonor-P', hbonds.prot_don_id],
                      ['HBondAccept-P', hbonds.prot_acc_id]]:
            if not len(group[1]) == 0:
                self.select_by_ids(group[0], group[1], restrict=self.protname)
        for group in [['HBondDonor-L', hbonds.lig_don_id],
                      ['HBondAccept-L', hbonds.lig_acc_id]]:
            if not len(group[1]) == 0:
                self.select_by_ids(group[0], group[1], restrict=self.ligname)
        for i in hbonds.ldon_id:
            cmd.select('tmp_bs', 'id %i & %s' % (i[0], self.protname))
            cmd.select('tmp_lig', 'id %i & %s' % (i[1], self.ligname))
            cmd.distance('HBonds', 'tmp_bs', 'tmp_lig')
        for i in hbonds.pdon_id:
            cmd.select('tmp_bs', 'id %i & %s' % (i[1], self.protname))
            cmd.select('tmp_lig', 'id %i & %s' % (i[0], self.ligname))
            cmd.distance('HBonds', 'tmp_bs', 'tmp_lig')
        if self.object_exists('HBonds'):
            cmd.set('dash_color', 'blue', 'HBonds')