docs: def from_dict(self, document):
          """Create functional data object from JSON document retrieved from
          database.
  
          Parameters
          ----------
          document : JSON
              Json document in database
  
          Returns
          -------
          FunctionalDataHandle
              Handle for functional data object
          """
          identifier = str(document['_id'])
          active = document['active']
          # The directory is not materilaized in database to allow moving the
          # base directory without having to update the database.
          directory = os.path.join(self.directory, identifier)
          timestamp = datetime.datetime.strptime(document['timestamp'], '%Y-%m-%dT%H:%M:%S.%f')
          properties = document['properties']
          return FunctionalDataHandle(identifier, properties, directory, timestamp=timestamp, is_active=active)