public function addNamespace($prefix, $uri)
    {
        if (empty($prefix))
            throw new \InvalidArgumentException('The prefix may not be emtpy or NULL.');
        if (empty($uri))
            throw new \InvalidArgumentException('The uri may not be empty or NULL.');

        $this->namespaces[$prefix] = $uri;

        return $this;
    }
public function addNamespace($prefix, $uri)
    {
        if (empty($prefix))
            throw new \InvalidArgumentException('The prefix may not be emtpy or NULL.');
        if (empty($uri))
            throw new \InvalidArgumentException('The uri may not be empty or NULL.');

        $this->namespaces[$prefix] = $uri;

        return $this;
    }
public function addNamespace ( $ prefix , $ uri ) { if ( empty ( $ prefix ) ) throw new \ InvalidArgumentException ( 'The prefix may not be emtpy or NULL.' ) ; if ( empty ( $ uri ) ) throw new \ InvalidArgumentException ( 'The uri may not be empty or NULL.' ) ; $ this -> namespaces [ $ prefix ] = $ uri ; return $ this ; }
Add a XML namespace to the internal list of namespaces. After that,
custom channel elements can be used properly to generate a valid feed.

@access   public
@param    string $prefix namespace prefix
@param    string $uri namespace name (URI)
@return   self
@link     http://www.w3.org/TR/REC-xml-names/
@throws   \InvalidArgumentException if the prefix or uri is empty or NULL.
Add a XML namespace to the internal list of namespaces . After that custom channel elements can be used properly to generate a valid feed .