docs: def check(doc, pointer, expected, raise_onerror=False):
      """Check if value exists into object.
  
      :param doc: the document base
      :param pointer: the path to search in
      :param expected: the expected value
      :param raise_onerror: should raise on error?
      :return: boolean
      """
      return Target(doc).check(pointer, expected, raise_onerror)