How to use the apio.util function in apio

def _rename_unpacked_dir(self):
        if self.uncompressed_name:
            unpack_dir = util.safe_join(
                self.packages_dir, self.uncompressed_name)
            package_dir = util.safe_join(
                self.packages_dir, self.package_name)
            if isdir(unpack_dir):
                rename(unpack_dir, package_dir)

def _get_headers():
    enc = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJwdWJsaWNfdG9rZW4iOiJ0' + \
          'b2tlbiBhNTk2OTUwNjFhYzRkMjBkZjEwNTFlZDljOWZjNGI4M2Q0NzAyYzA3I' + \
          'n0.POR6Iae_pSt0m6h-AaRi1X6QaRcnnfl9aZbTSV0BUJw'
    return {'Authorization': util.decode(enc).get('public_token')}

def _check_serial(self, board, board_data, ext_serial_port):
        if 'usb' not in board_data:
            raise Exception('Missing board configuration: usb')

        usb_data = board_data.get('usb')
        hwid = '{0}:{1}'.format(
            usb_data.get('vid'),
            usb_data.get('pid')
        )

        # Match the discovered serial ports
        serial_ports = util.get_serial_ports()
        if len(serial_ports) == 0:
            # Board not available
            raise Exception('board ' + board + ' not available')
        for serial_port_data in serial_ports:
            port = serial_port_data.get('port')
            if ext_serial_port and ext_serial_port != port:
                # If the --device options is set but it doesn't match
                # the detected port, skip the port.
                continue
            if hwid.lower() in serial_port_data.get('hwid').lower():
                if 'tinyprog' in board_data and \
                   not self._check_tinyprog(board_data, port):
                    # If the board uses tinyprog use its port detection
                    # to double check the detected port.
                    # If the port is not detected, skip the port.
                    continue

def _preserve_filemtime(self, lmdate):
        if lmdate is not None:
            timedata = parsedate_tz(lmdate)
            lmtime = mktime(timedata[:9])
            util.change_filemtime(self._destination, lmtime)