code: def load(self):
          
          #We load the database even when it is not configured to be
          #writable. After all, the user may decide part-way through a session to
          #begin writing again, and then we would want a history up to that point
          #to be valid.
          from os import path
          if path.isfile(self.dbpath):
              import json
              with open(self.dbpath) as f:
                  jdb = json.load(f)
                  self.entities = jdb["entities"]
                  self.uuids = jdb["uuids"]
docs: Deserializes the database from disk.