code: def classify(self, peer_dir_meta):
          
          assert self.operation is None
          # write("CLASSIFIY", self, peer_dir_meta)
          # Note: We pass False if the entry is not listed in the metadata.
          #       We pass None if we don't have metadata all.
          peer_entry_meta = peer_dir_meta.get(self.name, False) if peer_dir_meta else None
          # write("=>", self, peer_entry_meta)
          if self.local:
              self.local.classify(peer_dir_meta)
              self.local_classification = self.local.classification
          elif peer_entry_meta:
              self.local_classification = "deleted"
          else:
              self.local_classification = "missing"
  
          if self.remote:
              self.remote.classify(peer_dir_meta)
              self.remote_classification = self.remote.classification
          elif peer_entry_meta:
              self.remote_classification = "deleted"
          else:
              self.remote_classification = "missing"
  
          c_pair = (self.local_classification, self.remote_classification)
  
          self.operation = operation_map.get(c_pair)
          if not self.operation:
              raise RuntimeError(
                  "Undefined operation for pair classification {}".format(c_pair)
              )
  
          if PRINT_CLASSIFICATIONS:
              write("classify {}".format(self))
          # if not entry.meta:
          # assert self.classification in PAIR_CLASSIFICATIONS
          assert self.operation in PAIR_OPERATIONS
          return self.operation
docs: Classify entry pair.