Nb Mypy

Nb Mypy is a facility to automatically run mypy on Jupyter notebook cells as they are executed, whilst retaining information about the execution history.

Installation

• Nb Mypy relies on the packages mypy and astor, but those should be automatically installed.
• Nb Mypy can be installed like:

python3 -m pip install nb_mypy

Once installed, you can load it via %load_ext nb_mypy in a cell of a Jupyter notebook using the IPython kernel.

Installation from source

The package can also be installed from source, using pip:

python3 -m pip install .

Usage

In Jupyter notebooks where you want to apply automatic type checking, you can load this extension to do type checking by executing (in a code cell) the line magic %load_ext nb_mypy.

With the line magic %nb_mypy you can modify the behaviour of Nb Mypy

Here are the ways to use the line magic %nb_mypy

• %nb_mypy -v: show version
• %nb_mypy: show the current state
• %nb_mypy On: enable automatic type checking
• %nb_mypy Off: disable automatic type checking
• %nb_mypy DebugOn: enable debug mode
• %nb_mypy DebugOff: disable debug mode
• %nb_mypy mypy-options [OPTIONS]: Provide extra options to mypy (for example --strict)

Load automatically

This package is an iPython extension, thus it can be loaded automatically by adding the following line to your iPython configuration file.

c.InteractiveShellApp.extensions = ['nb_mypy']

The configuration file can (probably) be found at ~/.ipython/profile_default/ipython_config.py or created by executing ipython profile create. To add options, for instance, always have strict type checking on, you can add the following.

c.InteractiveShellApp.exec_lines = ['%nb_mypy mypy-options --strict']

Examples

For examples, see the Jupyter notebook Nb_Mypy.ipynb.