public function usort( \Closure $callback )
	{
		usort( $this->data, $callback );
		reset( $this->data );

		return $this;
	}
public function usort( \Closure $callback )
	{
		usort( $this->data, $callback );
		reset( $this->data );

		return $this;
	}
public function usort ( \ Closure $ callback ) { usort ( $ this -> data , $ callback ) ; reset ( $ this -> data ) ; return $ this ; }
Provide a callback to use for sorting the data.

@param \Closure $callback The callback to be used.

@return $this
Provide a callback to use for sorting the data .