def append_zeros(self, num):
        """Append zeros to an Index

        Parameters
        ----------
        num: int
            number of zeros to append
        """
        if num == 0:
            return self
        new_items = F.zeros((num,), dtype=F.int64, ctx=F.cpu())
        if len(self) == 0:
            return Index(new_items, self.dtype)
        else:
            tensor = self.tousertensor()
            tensor = F.cat((tensor, new_items), dim=0)
            return Index(tensor, self.dtype)
Append zeros to an Index

        Parameters
        ----------
        num: int
            number of zeros to append
        
python/dgl/utils/internal.py