final public function offsetSet($key, $value)
	{
		$key = (string) $key;

		if ( array_key_exists($key, $this->_stack) ) {
			throw new \DomainException('Key already exists.');
		}

		$this->_stack[$key] = $value;
	}
final public function offsetSet($key, $value)
	{
		$key = (string) $key;

		if ( array_key_exists($key, $this->_stack) ) {
			throw new \DomainException('Key already exists.');
		}

		$this->_stack[$key] = $value;
	}
final public function offsetSet ( $ key , $ value ) { $ key = ( string ) $ key ; if ( array_key_exists ( $ key , $ this -> _stack ) ) { throw new \ DomainException ( 'Key already exists.' ) ; } $ this -> _stack [ $ key ] = $ value ; }
Sets a value to the new named location with array notation.

@param string $key
@param mixed $value
@throws DomainException
Sets a value to the new named location with array notation .