public function pushKey($layer)
    {
        $this->base .= $this->delimiter . str_replace($this->delimiter, $this->placeholder, $layer);
        return $this->getBase();
    }
public function pushKey($layer)
    {
        $this->base .= $this->delimiter . str_replace($this->delimiter, $this->placeholder, $layer);
        return $this->getBase();
    }
public function pushKey ( $ layer ) { $ this -> base .= $ this -> delimiter . str_replace ( $ this -> delimiter , $ this -> placeholder , $ layer ) ; return $ this -> getBase ( ) ; }
Add a layer of depth to the key hierarchy

@param string $layer

@return string The new base key
Add a layer of depth to the key hierarchy