    element.getEmbeddedCells([opt])

Return an array of all the embedded cells of an element. If all you need is `id`'s of all the embedded cells, use `element.get('embeds')`. If `opt.deep` is `true`, all the deeply embedded cells will be returned. The order in which the cells are returned depends on the search algorithm used. By default, Depth-first search (DFS) algorithm is used. If `opt.breadthFirst` is `true`, the Breadth-first search algorithm will be used instead.