code: def get_file_url_for_heroku_app(self, source_app):
          
          self.print_message("Getting backup url for Heroku app '%s'" % source_app)
          args = [
              "heroku",
              "pg:backups:url",
              "--app=%s" % source_app,
          ]
          if self.args.use_pgbackups:
              args = [
                  "heroku",
                  "pgbackups:url",
                  "--app=%s" % source_app,
              ]
          return subprocess.check_output(args).strip().decode('ascii')
docs: Get latest backup URL from heroku pg:backups (or pgbackups).