code: def execute(self, example_groups):
          
          total_successes, total_errors, total_skipped = 0, 0, 0
          for group in example_groups:
              runner = ExampleRunner(group, self.formatter)
              successes, errors, skips = runner.run()
              total_successes += successes
              total_errors += errors
              total_skipped += skips
          return total_successes, total_errors, total_skipped
docs: Runs the specs. Returns a tuple indicating the
          number of (succeses, failures, skipped)>