mimedecode requires Python2; preferred versions are 2.6 or 2.7.
mimedecode requires m_lib library.

First install m_lib.

To install the program from sources system-wide run run the following
command:

   sudo python setup.py install -O2

If you don't want to install it system-wide you can install it in your
home directory; run run the following command:

   python setup.py install -O2 --user

Option '--user' only available in Python 2.6 or 2.7. The command
installs mimedecode into $HOME/.local/bin; add the directory to your
$PATH.

Or you can simple drop mimedecode.py somewhere in your $PATH.