def _is_4d(grouped_dicoms):
    """
    Use this function to detect if a dicom series is a ge 4d dataset
    NOTE: Only the first slice will be checked so you can only provide an already sorted dicom directory
    (containing one series)
    """
    header = grouped_dicoms[0][0]
    if len(grouped_dicoms) > 1:
        return True
    return False
