Tanguy Le Carrour <tanguy@bioneland.org> writes:

> * gnu/packages/python-check.scm (python-mypy-extensions): New variable.

[...]

> +(define-public python-mypy-extensions
> +  (package
> +    (name "python-mypy-extensions")
> +    (version "0.4.3")
> +    (source
> +      (origin
> +        (method url-fetch)
> +        (uri (pypi-uri "mypy_extensions" version))
> +        (sha256
> +         (base32
> +          "1a04qsk8hd1lqns8w1j7cr0vmvbhg450di5k1i16kqxkbf7q30id"))))
> +    (build-system python-build-system)
> +    (arguments `(#:tests? #f)); no tests
> +    (home-page "https://github.com/python/mypy_extensions")
> +    (synopsis "Experimental extensions for MyPy.")
                                                 ^^^
No '.'.   --------->

> +    (description "The @code{python-mypy-extensions} module defines experimental
> +extensions to the standard 'typing' module that are supported by the mypy typechecker.")

@code{typing}.  Also try to keep description lines shorter than 78
characters.  This should probably also say 'MyPy' (capitalized)?