The following is still very readable:

```python
                        current_threshold = (X[samples[p - 1], current_feature]
                                                         + X[samples[p], current_feature]) / 2.0
```

or alternatively:

```
                        current_threshold = (
                            X[samples[p - 1], current_feature] + X[samples[p], current_feature]) / 2.0
```