def initialize_options(self):
    self.manprefix = None
install.initialize_options(self)

def finalize_options(self):
    if self.manprefix is None:
        self.manprefix = 'DEFAULT MAN PREFIX PATH IF THE OPTION IS NOT SET'
install.finalize_options(self)

def run(self):
    pass
Python: установка справочных страниц в проекте на основе distutils