Incorrect calculation of Halstead metrics and Maintainability Index

Incorrect calculation of Halstead metrics and Maintainability Index: a task in harbor-swesmith-rl-artifacts: Harbor SWE-Smith 强化学习数据产物 (Harbor dataset). I found a bug in the latest version of Radon. The metrics calculations in the metrics.py file are producing incorrect results.

The task

I found a bug in the latest version of Radon. The metrics calculations in the `metrics.py` file are producing incorrect results.

Part of keryszhan/harbor-swesmith-rl-artifacts.