title: DynamoDB2 and Boto 2.9.5 bad request on batch query and single item get
body: <p>I am having trouble doing any single or batch query with boto 2.9.5 using the DynamoDB2 API</p>
  
  <p>I need to do a batch query like this:</p>
  
  <pre><code>one_org = Table('[table-name]').batch_get(keys=[
          {'key': '[user-id-hash]'},
          {'key': '[user-id-hash]'},
          {'key': '[user-id-hash]'},
          {'key': '[user-id-hash]'},
      ])
  
  for user in one_org:
      for key, value in user.items():
          print key, value
  </code></pre>
  
  <p>I keep getting this exception:</p>
  
  <pre><code>boto.dynamodb2.exceptions.ValidationException: ValidationException: 400 Bad Request
  {
      u'message': u'The provided key element does not match the schema', 
      u'__type': u'com.amazon.coral.validate#ValidationException'
  }
  </code></pre>
  
  <p>Given this message I'd think there'd be a problem with the name of the key, but our key is called key, so it doesn't make any sense to me.</p>
  
  <p>I included the stack trace below:</p>
  
  <pre><code>Traceback (most recent call last):
    File "aws/interfaces.py", line 38, in &lt;module&gt;
      for user in one_org:
    File "/home/kasper/Falcon/thenest/venv/local/lib/python2.7/site-packages/boto/dynamodb2/results.py", line 59, in next
      self.fetch_more()
    File "/home/kasper/Falcon/thenest/venv/local/lib/python2.7/site-packages/boto/dynamodb2/results.py", line 141, in fetch_more
      results = self.the_callable(*args, **kwargs)
    File "/home/kasper/Falcon/thenest/venv/local/lib/python2.7/site-packages/boto/dynamodb2/table.py", line 949, in _batch_get
      raw_results = self.connection.batch_get_item(request_items=items)
    File "/home/kasper/Falcon/thenest/venv/local/lib/python2.7/site-packages/boto/dynamodb2/layer1.py", line 152, in batch_get_item
      body=json.dumps(params))
    File "/home/kasper/Falcon/thenest/venv/local/lib/python2.7/site-packages/boto/dynamodb2/layer1.py", line 1479, in make_request
      retry_handler=self._retry_handler)
    File "/home/kasper/Falcon/thenest/venv/local/lib/python2.7/site-packages/boto/connection.py", line 852, in _mexe
      status = retry_handler(response, i, next_sleep)
    File "/home/kasper/Falcon/thenest/venv/local/lib/python2.7/site-packages/boto/dynamodb2/layer1.py", line 1518, in _retry_handler
      response.status, response.reason, data)
  boto.dynamodb2.exceptions.ValidationException: ValidationException: 400 Bad Request
  {u'message': u'The provided key element does not match the schema', u'__type': u'com.amazon.coral.validate#ValidationException'}
  </code></pre>