code: def install_prefix(self):
          
          return self.get(property_name='install_prefix',
                          default='/usr/local' if sys.prefix == '/usr' and self.on_debian else sys.prefix)
docs: The absolute pathname of the installation prefix to use (a string).
  
          This property is based on :data:`sys.prefix` except that when
          :data:`sys.prefix` is ``/usr`` and we're running on a Debian derived
          system ``/usr/local`` is used instead.
  
          The reason for this is that on Debian derived systems only apt (dpkg)
          should be allowed to touch files in ``/usr/lib/pythonX.Y/dist-packages``
          and ``python setup.py install`` knows this (see the ``posix_local``
          installation scheme in ``/usr/lib/pythonX.Y/sysconfig.py`` on Debian
          derived systems). Because pip-accel replaces ``python setup.py
          install`` it has to replicate this logic. Inferring all of this from
          the :mod:`sysconfig` module would be nice but that module wasn't
          available in Python 2.6.