def __get_all_lowpoints(dfs_data):
lowpoint_1_lookup = {}<EOL>lowpoint_2_lookup = {}<EOL>ordering = dfs_data['<STR_LIT>']<EOL>for node in ordering:<EOL><INDENT>low_1, low_2 = __get_lowpoints(node, dfs_data)<EOL>lowpoint_1_lookup[node] = low_1<EOL>lowpoint_2_lookup[node] = low_2<EOL><DEDENT>return lowpoint_1_lookup, lowpoint_2_lookup<EOL>
Calculates the lowpoints for each node in a graph.