code: def create_xref(self):
          
          log.debug("Creating Crossreferences (XREF)")
          tic = time.time()
  
          # TODO on concurrent runs, we probably need to clean up first,
          # or check that we do not write garbage.
  
          # TODO multiprocessing
          for c in self._get_all_classes():
              self._create_xref(c)
  
          log.info("End of creating cross references (XREF)")
          log.info("run time: {:0d}min {:02d}s".format(*divmod(int(time.time() - tic), 60)))
docs: Create Class, Method, String and Field crossreferences
          for all classes in the Analysis.
  
          If you are using multiple DEX files, this function must
          be called when all DEX files are added.
          If you call the function after every DEX file, the
          crossreferences might be wrong!