public function fileHeader($header)
    {
        $this->fileHeader = is_array($header) ? implode("\n", $header) : (string)$header;
        return $this;
    }
public function fileHeader($header)
    {
        $this->fileHeader = is_array($header) ? implode("\n", $header) : (string)$header;
        return $this;
    }
public function fileHeader ( $ header ) { $ this -> fileHeader = is_array ( $ header ) ? implode ( "\n" , $ header ) : ( string ) $ header ; return $ this ; }
Lines that will be added as comment to the beginning of the output file

@param array|string $header
@return $this
Lines that will be added as comment to the beginning of the output file