def METHOD_NAME(mocker: MockFixture, session: Session) -> None:
    """
    Test that existing dashboards are updated with new charts.
    """
    from superset import security_manager
    from superset.commands.importers.v1.assets import ImportAssetsCommand
    from superset.models.dashboard import dashboard_slices
    from superset.models.slice import Slice
    mocker.patch.object(security_manager, "can_access", return_value=True)
    engine = session.get_bind()
    Slice.metadata.create_all(engine)  # pylint: disable=no-member
    base_configs = {
        **copy.deepcopy(databases_config),
        **copy.deepcopy(datasets_config),
        **copy.deepcopy(charts_config_2),
        **copy.deepcopy(dashboards_config_2),
    }
    new_configs = {
        **copy.deepcopy(databases_config),
        **copy.deepcopy(datasets_config),
        **copy.deepcopy(charts_config_1),
        **copy.deepcopy(dashboards_config_1),
    }
    expected_number_of_dashboards = len(dashboards_config_1)
    expected_number_of_charts = len(charts_config_1)
    ImportAssetsCommand._import(session, base_configs)
    ImportAssetsCommand._import(session, new_configs)
    dashboard_ids = session.scalars(
        select(dashboard_slices.c.dashboard_id).distinct()
    ).all()
    chart_ids = session.scalars(select(dashboard_slices.c.slice_id)).all()
    assert len(chart_ids) == expected_number_of_charts
    assert len(dashboard_ids) == expected_number_of_dashboards