<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_metrics_event_rate(self, start_time=None, end_time=None, result_type=None, **kwargs):
 """ Percentage of queries with an associated event. The percentage of queries using the **natural_language_query** parameter that have a corresponding \"click\" event over a specified time window. This metric requires having integrated event tracking in your application using the **Events** API. :param datetime start_time: Metric is computed from data recorded after this timestamp; must be in `YYYY-MM-DDThh:mm:ssZ` format. :param datetime end_time: Metric is computed from data recorded before this timestamp; must be in `YYYY-MM-DDThh:mm:ssZ` format. :param str result_type: The type of result to consider when calculating the metric. :param dict headers: A `dict` containing the request headers :return: A `DetailedResponse` containing the result, headers and HTTP status code. :rtype: DetailedResponse """


        headers = {}
        if 'headers' in kwargs:
            headers.update(kwargs.get('headers'))
        sdk_headers = get_sdk_headers('discovery', 'V1',
                                      'get_metrics_event_rate')
        headers.update(sdk_headers)

        params = {
            'version': self.version,
            'start_time': start_time,
            'end_time': end_time,
            'result_type': result_type
        }

        url = '/v1/metrics/event_rate'
        response = self.request(
            method='GET',
            url=url,
            headers=headers,
            params=params,
            accept_json=True)
        return response