#define be_ifg_nodes_iter_size(self) ((self)->impl->nodes_iter_size)
#define be_ifg_neighbours_iter_size(self) ((self)->impl->neighbours_iter_size)
+#define be_ifg_cliques_iter_size(self) ((self)->impl->cliques_iter_size)
#define be_ifg_free(self) ((self)->impl->free(self))
#define be_ifg_connected(self,a,b) ((self)->impl->connected(self, a, b))