code: def _entity_to_region_map(self):
          
          entity_to_region = {}
          for key in self.get_all_keys():
              layer, rx, ry = struct.unpack('>BHH', key)
              if layer != 4:
                  continue
              stream = io.BytesIO(self.get(layer, rx, ry))
              num_entities = sbon.read_varint(stream)
              for _ in range(num_entities):
                  uuid = sbon.read_string(stream)
                  if uuid in entity_to_region:
                      raise ValueError('Duplicate UUID {}'.format(uuid))
                  entity_to_region[uuid] = (rx, ry)
          return entity_to_region
docs: A dict whose keys are the UUIDs (or just IDs, in some cases) of
          entities, and whose values are the `(rx, ry)` coordinates in which that
          entity can be found. This can be used to easily locate particular
          entities inside the world.