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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_invalid_mailbox(value, endchars):
 """ Read everything up to one of the chars in endchars. This is outside the formal grammar. The InvalidMailbox TokenList that is returned acts like a Mailbox, but the data attributes are None. """

    invalid_mailbox = InvalidMailbox()
    while value and value[0] not in endchars:
        if value[0] in PHRASE_ENDS:
            invalid_mailbox.append(ValueTerminal(value[0],
                                                 'misplaced-special'))
            value = value[1:]
        else:
            token, value = get_phrase(value)
            invalid_mailbox.append(token)
    return invalid_mailbox, value