public function add($key, $value)
    {
        $this->collection[$key]       = $value;
        $this->indices[$this->length] = $key;
        $this->length++;

        return $this;
    }
public function add($key, $value)
    {
        $this->collection[$key]       = $value;
        $this->indices[$this->length] = $key;
        $this->length++;

        return $this;
    }
public function add ( $ key , $ value ) { $ this -> collection [ $ key ] = $ value ; $ this -> indices [ $ this -> length ] = $ key ; $ this -> length ++ ; return $ this ; }
Add data to the collection.

@param  string $key
@param  mixed  $value
@return self
Add data to the collection .