# forge.signals.then

```python
forge.signals.then(first: np.ndarray | ConditionTree, second: np.ndarray | ConditionTree, /, *, within: int, name: str | None = None, note: str | None = None) -> ConditionTree
```

True where ``second`` becomes true, if ``first`` became true 1 to ``within`` bars earlier.

Only the bar each one becomes true counts. The bar ``first`` became true is not counted in the
window, so both becoming true on the same bar is not a sequence. ``within=5`` means ``second``
on any of the 5 bars after ``first``'s bar.

Since Forge API 1.