title: Boto3 get_cost_and_usage filter Getting zero cost based on tag
body: <p>I am trying to get cost consumed by each tag in AWS using Boto3 get_cost_and_usage() method.</p>
  
  <p>In filter, I am passing tag key and its value but I am getting zero cost each time.</p>
  
  <p>In <code>get_cost_and_usage()</code> I passed TimePeriod and Tags in the filter but I am always getting zero cost.</p>
  
  <pre><code>import boto3
  client = boto3.client('ce')
  
  response = client.get_cost_and_usage(
      TimePeriod={
          'Start': '2019-07-01',
          'End': '2019-08-01'
      },
      Metrics=['AmortizedCost'],
      Granularity='MONTHLY',
      Filter={
           "Tags": {
               "Key": "Key",
               "Values": [
                   "kubernetes.io/cluster/bmchugh-zfllx",
                ]
           }
       }
  )
  from pprint import pprint
  pprint(response)
  </code></pre>
  
  <p>i am not getting any error but also not getting any cost getting bellow result.</p>
  
  <pre><code>{'ResponseMetadata': {'HTTPHeaders': {'content-length': '160',
                                        'content-type': 'application/x-amz-json-1.1',
                                        'date': 'Fri, 23 Aug 2019 05:46:10 GMT',
                                        'x-amzn-requestid': 'f3c3d4f0-1083-4b3d-94d3-39477b4aed41'},
                        'HTTPStatusCode': 200,
                        'RequestId': 'f3c3d4f0-1083-4b3d-94d3-39477b4aed41',
                        'RetryAttempts': 0},
   'ResultsByTime': [{'Estimated': False,
                      'Groups': [],
                      'TimePeriod': {'End': '2019-08-01', 'Start': '2019-07-01'},
                      'Total': {'AmortizedCost': {'Amount': '0',
                                                  'Unit': 'USD'}}}]}
  </code></pre>