:param signal: top signal of hidden operator tree
        :note: operator tree is constrained by signals with hidden==False
        :note: statement nodes are not connected automatically

def lazyLoadNet(self, signal: RtlSignalBase):
        """
        :param signal: top signal of hidden operator tree
        :note: operator tree is constrained by signals with hidden==False
        :note: statement nodes are not connected automatically
        """
        d_cnt = len(signal.drivers)
        if d_cnt == 1:
            driver = signal.drivers[0]
            if isinstance(driver, Operator):
                d = self.addOperatorAsLNode(driver)
                if isinstance(d, LNode):
                    c, _ = self.netCtxs.getDefault(signal)
                    c.addDriver(d.east[0])
                else:
                    self.netCtxs.joinNetsByKeyVal(signal, d)
        elif d_cnt == 0 and signal.defVal._isFullVld():
            raise AssertionError("Value of this net should have been already rendered")
        else:
            raise AssertionError(signal, signal.drivers)