/**
* Creates a bool mapping.
*
* @param string $message The error message
*
* @return Mapping
*/
public function bool($message = 'error.bool')
{
$mapping = new Mapping(new Emitter(), $this->extensions);
$mapping->transform(new Transformer\BoolTransformer());
$mapping->validate(new Constraint\Type($message, 'bool'));
return $mapping;
}