Send POST request to execute Ndrive API

        :param func: The function name you want to execute in Ndrive API.
        :param params: Parameter data for HTTP request.

        :returns: ``metadata`` when success or ``False`` when failed

def POST(self, func, data):
        """Send POST request to execute Ndrive API

        :param func: The function name you want to execute in Ndrive API.
        :param params: Parameter data for HTTP request.

        :returns: ``metadata`` when success or ``False`` when failed
        """
        s, message = self.checkAccount()
        if s is False:
            return False, message

        url = nurls[func]
        r = self.session.post(url, data = data)
        r.encoding = 'utf-8'

        if self.debug:
            print r.text.encode("utf-8")

        try:
            metadata = json.loads(r.text)
            message = metadata['message']
            if message == 'success':
                try:
                    return True, metadata['resultvalue']
                except:
                    return True, metadata['resultcode']
            else:
                return False, "Error %s: %s" %(func, message)
        except:
            #for e in sys.exc_info():
            #    print e
            #sys.exit(1)
            return False, "Error %s: Failed to send POST request" %func