code: def wrap(self, value, session=None):
          ''' Validates that ``value`` is an ObjectId (or hex representation
              of one), then returns it '''
          self.validate_wrap(value)
          if isinstance(value, bytes) or isinstance(value, basestring):
              return ObjectId(value)
          return valuf wrap(self, value, session=None):
          ''' Validates that ``value`` is an ObjectId (or hex representation
              of one), then returns it '''
          self.validate_wrap(value)
          if isinstance(value, bytes) or isinstance(value, basestring):
              return ObjectId(value)
          return value
docs: Validates that ``value`` is an ObjectId (or hex representation
              of one), then returns it