src/AbstractCache.php
protected function assertIterable($subject, $msg): void
    {
        $iterable = function_exists('is_iterable')
            ? is_iterable($subject)
            : is_array($subject) || $subject instanceof Traversable;
        
        if (!$iterable) {
            throw new InvalidArgumentException($msg);
        }
    }
protected function assertIterable($subject, $msg): void
    {
        $iterable = function_exists('is_iterable')
            ? is_iterable($subject)
            : is_array($subject) || $subject instanceof Traversable;
        
        if (!$iterable) {
            throw new InvalidArgumentException($msg);
        }
    }
protected function assertIterable ( $ subject , $ msg ) : void { $ iterable = function_exists ( 'is_iterable' ) ? is_iterable ( $ subject ) : is_array ( $ subject ) || $ subject instanceof Traversable ; if ( ! $ iterable ) { throw new InvalidArgumentException ( $ msg ) ; } }
Assert that the keys are an array or traversable

@param iterable $subject
@param string   $msg
@return void
@throws InvalidArgumentException if subject are not iterable
Assert that the keys are an array or traversable