code: def create_back_links(env):
      if env.needs_workflow['backlink_creation']:
          return
      needs = env.needs_all_needs
      for key, need in needs.items():
          for link in need["links"]:
              link_main = link.split('.')[0]
              try:
                  link_part = link.split('.')[1]
              except IndexError:
                  link_part = None
              if link_main in needs:
                  if key not in needs[link_main]["links_back"]:
                      needs[link_main]["links_back"].append(key)
                  if link_part is not None:
                      if link_part in needs[link_main]['parts']:
                          if 'links_back' not in needs[link_main]['parts'][link_part].keys():
                              needs[link_main]['parts'][link_part]['links_back'] = []
                          needs[link_main]['parts'][link_part]['links_back'].append(key)
      env.needs_workflow['backlink_creation'] = True