def incoming_blocks(self, block):
        """
        Yield (incoming block, number of stack pops) pairs for *block*.
        """
        for i, pops in block.incoming_jumps.items():
            if i in self.liveblocks:
                yield self.blocks[i], pops

        Yield (incoming block, number of stack pops) pairs for *block*.
        
numba/core/controlflow.py