title: Python Boto3 Module fetching API Keys with position parameter raising an exception
body: <p>I tried to fetch list of API Keys created in my aws account.  There are 50 Api keys.  I want to list 10 Api Keys per request. Here is the code snippet.</p>
  
  <pre><code>import boto3
  
  client = boto3.client('apigateway')
  response = client.get_api_keys(
      limit=10,
      position="1",
  )
  print response
  </code></pre>
  
  <p>When I run the script, It is showing an error, </p>
  
  <pre><code>Traceback (most recent call last):
    File "test.py", line 7, in &lt;module&gt;
      position="1",
    File "C:\Users\Murthy\workspace\my_project\venv\lib\site-packages\botocore\client.py", line 310, in _api_call
      return self._make_api_call(operation_name, kwargs)
    File "C:\Users\Murthy\workspace\my_project\venv\lib\site-packages\botocore\client.py", line 599, in _make_api_call
      raise error_class(parsed_response, operation_name)
  botocore.errorfactory.BadRequestException: An error occurred (BadRequestException) when calling the GetApiKeys operation: Invalid position parameter
  </code></pre>
  
  <p>Am I doing wrong ?</p>
  
  <p>Also maximum results per query is 500. How do we know total number of results to perform the pagination ?</p>