src/Zicht/Itertools/lib/Traits/GetterTrait.php
public function has($offset)
    {
        if ($this instanceof \Traversable) {
            foreach ($this as $key => $_) {
                if ($key === $offset) {
                    return true;
                }
            }
        }
        return false;
    }
public function has($offset)
    {
        if ($this instanceof \Traversable) {
            foreach ($this as $key => $_) {
                if ($key === $offset) {
                    return true;
                }
            }
        }
        return false;
    }
Returns true when a key exists of the same type and value as $OFFSET

@param mixed $offset
@return bool