Get file as MIMEBase message

def get_attachment(self, file_path):
        '''Get file as MIMEBase message'''

        try:
            file_ = open(file_path, 'rb')
            attachment = MIMEBase('application', 'octet-stream')
            attachment.set_payload(file_.read())
            file_.close()
            encoders.encode_base64(attachment)

            attachment.add_header('Content-Disposition', 'attachment',
                                  filename=os.path.basename(file_path))
            return attachment
        except IOError:
            traceback.print_exc()
            message = ('The requested file could not be read. Maybe wrong '
                       'permissions?')
            print >> sys.stderr, message
            sys.exit(6)