def do_claim(self):
self.do_set_row_col_sizes({<EOL>i: self._sizes[child]<EOL>for i, child in enumerate(self._children)<EOL>if self._sizes[child] is not None<EOL>})<EOL>min_cell_rects = {<EOL>self.do_get_row_col(i): child.claimed_rect<EOL>for i, child in enumerate(self._children)<EOL>}<EOL>return self._grid.make_claim(min_cell_rects)<EOL>
Claim enough space for all the child widgets put together in the 
direction of the layout (e.g. horizontal for `HBox`, vertical for 
`VBox`) and just enough space for the largest child widget in the 
opposite direction.