def get_py4DSTEM_topgroup(h5_file):
    """
    Accepts an open h5py File boject. Returns string of the top group name. 
    """
    if '4DSTEM_experiment' in h5_file.keys():
        return '4DSTEM_experiment/'
    elif '4DSTEM_simulation' in h5_file.keys():
        return '4DSTEM_simulation/'
    else:
        return '4D-STEM_data/'
