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, value, display=False):
        if not value:
            return ""
        return "\n  " + "\n  ".join(encode(v) for v in value if v)