docs: def check(self, pointer, expected, raise_onerror=False):
          """Check if value exists into object.
  
          :param pointer: the path to search in
          :param expected: the expected value
          :param raise_onerror: should raise on error?
          :return: boolean
          """
          obj = self.document
          for token in Pointer(pointer):
              try:
                  obj = token.extract(obj, bypass_ref=True)
              except ExtractError as error:
                  if raise_onerror:
                      raise Error(*error.args)
                  logger.exception(error)
                  return False
          return obj == expected