# `GSInstance customBoolValueForKey:`

*Instance Method*

Returns the boolean value of the custom parameter for the specified key.

## Declaration

```swift
func customBoolValue(forKey key: String) -> Bool
```

```objc
- (BOOL) customBoolValueForKey:(NSString *) key;
```

```python
customBoolValueForKey_(key: str) -> bool
```

## Parameters

- `key` — The key.

## Return Value

The boolean value of the custom parameter.