code: def _setup_preferred_paths(self, preferred_conversion_paths):
          '''
          Add given valid preferred conversion paths
          '''
          for path in preferred_conversion_paths:
              for pair in pair_looper(path):
                  if pair not in self.converters:
                      log.warning('Invalid conversion path %s, unknown step %s' %
                                  (repr(path), repr(pair)))
                      break
              else:
                  # If it did not break, then add to dgraph
                  self.dgraph.add_preferred_path(*pathf _setup_preferred_paths(self, preferred_conversion_paths):
          '''
          Add given valid preferred conversion paths
          '''
          for path in preferred_conversion_paths:
              for pair in pair_looper(path):
                  if pair not in self.converters:
                      log.warning('Invalid conversion path %s, unknown step %s' %
                                  (repr(path), repr(pair)))
                      break
              else:
                  # If it did not break, then add to dgraph
                  self.dgraph.add_preferred_path(*path)
docs: Add given valid preferred conversion paths