def tryPrepare(self, pp: PrePrepare):
        """
        Try to send the Prepare message if the PrePrepare message is ready to
        be passed into the Prepare phase.
        """
        rv, msg = self.canPrepare(pp)
        if rv:
            self.doPrepare(pp)
        else:
            self.logger.debug("{} cannot send PREPARE since {}".format(self, msg))
Try to send the Prepare message if the PrePrepare message is ready to
        be passed into the Prepare phase.