public function setAuthor($author)
    {
        if ($author === null) {
            $this->author    = null;
        } else {
            $this->author    = (string)$author;
        }
        return $this;
    }
public function setAuthor($author)
    {
        if ($author === null) {
            $this->author    = null;
        } else {
            $this->author    = (string)$author;
        }
        return $this;
    }
public function setAuthor ( $ author ) { if ( $ author === null ) { $ this -> author = null ; } else { $ this -> author = ( string ) $ author ; } return $ this ; }
Sets  the author that will be used when committing the transaction

@param   string|null     $author      The author
@return  Transaction
Sets the author that will be used when committing the transaction