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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 open(self, writeAccess=False):
 """ Returns the sqlite database for the current thread. :return <variant> || None """

        host = self.database().writeHost() if writeAccess else self.database().host()
        pool = self.__pool[host]

        if self.__poolSize[host] >= self.__maxSize or pool.qsize():
            if pool.qsize() == 0:
                log.warning('Waiting for connection to database!!!')
            return pool.get()
        else:
            db = self.database()

            # process a pre-connect event
            event = orb.events.ConnectionEvent()
            db.onPreConnect(event)

            self.__poolSize[host] += 1
            try:
                conn = self._open(self.database(), writeAccess=writeAccess)
            except Exception:
                self.__poolSize[host] -= 1
                raise
            else:
                event = orb.events.ConnectionEvent(success=conn is not None, native=conn)
                db.onPostConnect(event)
                return conn