def METHOD_NAME():
    """Test _extract_data for extraction between signals"""
    # no ending
    test_string = "@start_of_data@start of data"
    output = _extract_data(test_string, 'data')
    assert output == ''
    # valid end, but no start to data
    test_string = "end of data@end_of_data:11@"
    output = _extract_data(test_string, 'data')
    assert output == ''
    test_string = "@start_of_data@all data@end_of_data:8@"
    output = _extract_data(test_string, 'data')
    assert output == 'all data'