def add_rows(self, num_rows):
        """Add blank rows to this frame.

        For existing fields, the rows will be extended according to their
        initializers.

        Parameters
        ----------
        num_rows : int
            The number of new rows
        """
        feat_placeholders = {}
        for key, col in self._columns.items():
            scheme = col.scheme
            ctx = F.context(col.data)
            if self.get_initializer(key) is None:
                self._set_zero_default_initializer()
            initializer = self.get_initializer(key)
            new_data = initializer(
                (num_rows,) + scheme.shape,
                scheme.dtype,
                ctx,
                slice(self._num_rows, self._num_rows + num_rows),
            )
            feat_placeholders[key] = new_data
        self._append(Frame(feat_placeholders))
        self._num_rows += num_rows
Add blank rows to this frame.

        For existing fields, the rows will be extended according to their
        initializers.

        Parameters
        ----------
        num_rows : int
            The number of new rows
        
python/dgl/frame.py