Copy dashboard

def copy_dash(self, dashboard_id):
        """Copy dashboard"""
        session = db.session()
        data = json.loads(request.form.get('data'))
        dash = models.Dashboard()
        original_dash = (
            session
            .query(models.Dashboard)
            .filter_by(id=dashboard_id).first())

        dash.owners = [g.user] if g.user else []
        dash.dashboard_title = data['dashboard_title']

        if data['duplicate_slices']:
            # Duplicating slices as well, mapping old ids to new ones
            old_to_new_sliceids = {}
            for slc in original_dash.slices:
                new_slice = slc.clone()
                new_slice.owners = [g.user] if g.user else []
                session.add(new_slice)
                session.flush()
                new_slice.dashboards.append(dash)
                old_to_new_sliceids['{}'.format(slc.id)] = \
                    '{}'.format(new_slice.id)

            # update chartId of layout entities
            # in v2_dash positions json data, chartId should be integer,
            # while in older version slice_id is string type
            for value in data['positions'].values():
                if (
                    isinstance(value, dict) and value.get('meta') and
                    value.get('meta').get('chartId')
                ):
                    old_id = '{}'.format(value.get('meta').get('chartId'))
                    new_id = int(old_to_new_sliceids[old_id])
                    value['meta']['chartId'] = new_id
        else:
            dash.slices = original_dash.slices
        dash.params = original_dash.params

        self._set_dash_metadata(dash, data)
        session.add(dash)
        session.commit()
        dash_json = json.dumps(dash.data)
        session.close()
        return json_success(dash_json)