def get_sidecar(fname, allowedfileformats='default'):
    """
    Loads sidecar or creates one
    """
    if allowedfileformats == 'default':
        allowedfileformats = ['.tsv', '.nii.gz']
    for f in allowedfileformats:
        fname = fname.split(f)[0]
    fname += '.json'
    if os.path.exists(fname):
        with open(fname) as fs:
            sidecar = json.load(fs)
    else:
        sidecar = {}
    if 'filestatus' not in sidecar:
        sidecar['filestatus'] = {}
        sidecar['filestatus']['reject'] = False
        sidecar['filestatus']['reason'] = []
    return sidecar
Loads sidecar or creates one