Currently ":type:" and ":rtype:" options in python docstrings have been fully supported in sphinx(https://sphinx-rtd-tutorial.readthedocs.io/en/latest/docstrings.html) and PyCharm(https://www.jetbrains.com/help/pycharm/using-docstrings-to-specify-types.html). Sphinx will generate python API documents with type annotations if these options exist in function docstrings. PyCharm also collects the type information in docstrings to detect potential coding mistakes and provide autocomplete support during python program development. There are already few interfaces in python API that have these options. We should add these options to the rest.