title: AWS Lambda Function Boto 3 filter_log_events Cannot Use endTime Parameter
body: <p>I'm trying to extract information from Cloudwatch logs to send a more customised email from an alert based on a metric. I'm creating a lambda function to try and extract information at a specified timeframe. However, when I specify a startTime and endTime, nothing comes back in the repsonse. I've looked at the documentation for Boto3 but it doesn't say much. I'm relatively new to python and AWS so any help would be great. An example of the code can be seen below:</p>
  
  <pre class="lang-py prettyprint-override"><code>import boto3
  import json
  import time
  from datetime import datetime
  from calendar import timegm
  
  # Create CloudWatch client
  clw = boto3.client('logs')
  
  
  def lambda_handler(event, context):
  
      # User defined for testing purposes
      name = 'Error Log Metric'
      namespace = 'User Defined Metrics'
  
      response = clw.describe_metric_filters(metricName=name,
              metricNamespace=namespace)
  
      LogGroupName = response['metricFilters'][0]['logGroupName']
      FilterPattern = response['metricFilters'][0]['filterPattern']
  
      StartTime = timegm(time.strptime('2020-06-15T00:00:00.000Z',
                         '%Y-%m-%dT%H:%M:%S.%fZ'))
      EndTime = timegm(time.strptime('2020-06-16T23:59:59.000Z',
                       '%Y-%m-%dT%H:%M:%S.%fZ'))
  
      filteredLogs = clw.filter_log_events(logGroupName=LogGroupName,
              filterPattern=FilterPattern,
              logStreamNamePrefix='TEST_PREFIX_NAME',
              startTime=StartTime, endTime=EndTime)
  
      print(filteredLogs)
  </code></pre>
  
  <p><strong>Response</strong></p>
  
  <pre><code>Response:
  null
  
  Request ID:
  "610a2849-3fef-46b2-b75e-450c4f37ec25"
  
  Function Logs:
  START RequestId: 610a2849-3fef-46b2-b75e-450c4f37ec25 Version: $LATEST
  {'events': [], 'searchedLogStreams': [], 'ResponseMetadata': {'RequestId': '04d59cfe-9069-4bb4-ad3b-7135a649d2e6', 'HTTPStatusCode': 200, 'HTTPHeaders': {'x-amzn-requestid': '04d59cfe-9069-4bb4-ad3b-7135a649d2e6', 'content-type': 'application/x-amz-json-1.1', 'content-length': '121', 'date': 'Tue, 16 Jun 2020 00:42:23 GMT'}, 'RetryAttempts': 0}}
  END RequestId: 610a2849-3fef-46b2-b75e-450c4f37ec25
  REPORT RequestId: 610a2849-3fef-46b2-b75e-450c4f37ec25  Duration: 299.88 ms Billed Duration: 300 ms Memory Size: 128 MB Max Memory Used: 71 MB  Init Duration: 315.90 ms
  </code></pre>