docs: def __get_all_lowpoints(dfs_data):
      """Calculates the lowpoints for each node in a graph."""
      lowpoint_1_lookup = {}
      lowpoint_2_lookup = {}
  
      ordering = dfs_data['ordering']
  
      for node in ordering:
          low_1, low_2 = __get_lowpoints(node, dfs_data)
          lowpoint_1_lookup[node] = low_1
          lowpoint_2_lookup[node] = low_2
  
      return lowpoint_1_lookup, lowpoint_2_lookup