I downloaded the hpackaget with the command:
wget https://pypi.python.org/packages/source/p/pyserial/pyserial-2.7.tar.gz#md5=794506184df83ef2290de0d18803dd11 --no-check-certificate
I decompressed it with:
tar xvf pyserial-2.7.tar.gz
Then I went into the the pyserial folder and installed it:
cd pyserial-2.7.tar.gz python setup.py install
Now I'm able to import the serial library on python. The thing was the that got wrong the download link, I actually got it from https://pypi.python.org/pypi/pyserial, but used the link above.