old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  # Author: Arne Neumann <discoursegraphs.programming@arne.cl>
  
  __author__ = 'Arne Neumann'
  __email__ = 'discoursegraphs.programming@arne.cl'
  __version__ = '0.1.2'
  
  # flake8: noqa
  
  from discoursegraphs.discoursegraph import (
      DiscourseDocumentGraph, EdgeTypes, create_token_mapping,
      get_annotation_layers, get_span,
      get_text, istoken, select_nodes_by_layer, select_edges_by, tokens2text,
      get_pointing_chains, get_top_level_layers)
  from discoursegraphs.readwrite.dot import print_dot
  from discoursegraphs.statistics import info
  from discoursegraphs.util import xmlprint, make_labels_explicit
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  # Author: Arne Neumann <discoursegraphs.programming@arne.cl>
  
  __author__ = 'Arne Neumann'
  __email__ = 'discoursegraphs.programming@arne.cl'
  __version__ = '0.1.2'
  
  # flake8: noqa
  
  from discoursegraphs.discoursegraph import (
      DiscourseDocumentGraph, EdgeTypes, create_token_mapping,
      get_annotation_layers, get_span,
      get_text, istoken, select_nodes_by_layer, select_edges_by, tokens2text,
      get_pointing_chains, get_top_level_layers)
  from discoursegraphs.readwrite.dot import print_dot
  from discoursegraphs.statistics import info
  from discoursegraphs.util import natural_sort_key, xmlprint, make_labels_explicit
  
subject: add natural_sort_key to main namespace