def load_installed_version(self):
        installed_packages = get_installed_pypackages()
        if self.package in installed_packages:
            self.version = "=={}".format(
                installed_packages[self.package].version)
def serialize(self):
        s = []
        for v in self:
            if isinstance(v, BaseConfig):
                v = v.serialize()
            s.append(v)
        return s