Pytype - https://github.com/google/pytype/
Pytype is a static analyzer for Python code.
Apache 2.0
pytype can statically analyze your Python code, and point out bugs and errors it finds. It works on any kind of code, and doesn't need any special directives to be useful.
However, it can additionally verify (and leverage) type annotations.
You currently need Python 2.7 to run pytype. (It can analyze Python 3, though)
git clone https://github.com/google/pytype.git
cd pytype
git submodule init
git submodule update
python setup.py install
pip install pyyaml
pytype your_python_code.py