def clear_value(self, idx):
        """Remove the value at the location
        """
        self.decref_value(self.getitem(idx))
        # it's necessary for the dtor which just decref every slot on it.
        self.zfill(idx, self._builder.add(idx, idx.type(1)))
Remove the value at the location
        
numba/cpython/listobj.py