def once_parser(cards: list) -> Optional[list]:
    '''
    parser for ONCE [2] issue mode
    Only one issuance transaction from asset owner allowed.
    '''

    first_issue = next(i for i in cards if i.type == "CardIssue")  # find first CardIssue

    filtered = [i for i in cards if i.type == "CardIssue" if i != first_issue]  #  drop all other CardIssues

    return [i for i in cards if i not in filtered]
def once_parser ( cards : list ) -> Optional [ list ] : first_issue = next ( i for i in cards if i . type == "CardIssue" ) filtered = [ i for i in cards if i . type == "CardIssue" if i != first_issue ] return [ i for i in cards if i not in filtered ]
parser for ONCE [2] issue mode
    Only one issuance transaction from asset owner allowed.