The library is available on pypi and to install the last available version, run this command:
$ pip install trendpy
To test the installation:
>>> import trendpy >>> trendpy.__version__
this should display the version installed on your system.
trendpy releases are also available on github (https://github.com/ronsenbergVI/trendpy). You first need to clone (or fork if you want to modify it) and
$ git clone https://github.com/ronsenbergVI/trendpy.git
$ cd trendpy
$ python setup.py build
$ python setup.py install