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 distance(self, pt):
        self.pt = pt
        x = self.x - self.pt.x
        y = self.y - self.pt.y
        return math.sqrt(x * x + y * y)