def get_mailbox(self, name, expiry=900):
        """
        A factory of sorts.. if we have an active mailbox with the given name
        return it.

        If we do not instantiate an instance of that mailbox and add it to our
        list of active mailboxes.

        Arguments:
        - `name`: The name of the mailbox our caller wants.
        - `expiry`: If we have to instantiate a mailbox give it this expiry
          time. Used so that boxes that are just being updated rarely expire
          and do not take up excess memory in the server. Defaults to 15
          minutes.
        """
        # The INBOX is case-insensitive but it is stored in our file system in
        # a case sensitive lower case fashion..
        #
        if name.lower() == "inbox":
            name = "inbox"
        if self.active_mailboxes in name:
            return self.active_mailboxes[name]

        # otherwise.. make an instance of this mailbox.
        #
        mbox = asimap.mbox.Mailbox(name, self, expiry=expiry)
        self.active_mailboxes[name] = mbox
        return mbox

    ##################################################################
    #
dataset/ETHPy150Open scanner/asimap/asimap/user_server.py/IMAPUserServer.get_mailbox/swapped operands of `in`