'Unpack a source package and check that setup.py exists'

def unpackPackageOnly(self, output=None):

    PimpPackage.unpackPackageOnly(self, output)
    self._buildDirname = os.path.join(self._db.preferences.buildDir, self.basename)
    setupname = os.path.join(self._buildDirname, 'setup.py')
    if ((not os.path.exists(setupname)) and (not NO_EXECUTE)):
        return 'no    setup.py    found    after    unpack    of    archive'
