def _read_genel_fields_until_char_blank(card_fields, istart):
    """somewhat loose parser helper function for GENEL"""
    new_fields = []
    i = 0
    for i, field in enumerate(card_fields[istart:]):
        if field is None:
            break
        if field.upper() in ['UD', 'K', 'S', 'Z']:
            break
        new_fields.append(field)
    return new_fields, istart + i
