title: In Boto3, how to create a Paginator for list_objects with additional keyword arguments?
body: <p>I'm using a <code>Paginator</code> to iterate over the contents of an S3 bucket (following <a href="http://boto3.readthedocs.io/en/latest/guide/paginators.html#creating-paginators" rel="noreferrer">http://boto3.readthedocs.io/en/latest/guide/paginators.html#creating-paginators</a>):</p>
  
  <pre><code>    client = boto3.client('s3')
      paginator = client.get_paginator('list_objects')
      page_iterator = paginator.paginate(Bucket=&lt;my_bucket&gt;)
  
      for page in page_iterator:
          for object in page['Contents']:
              key = object['Key']
  </code></pre>
  
  <p>In this example, the method name <code>'list_objects'</code> is passed as a string. However, I would actually like to use a 'partial' function <code>list_objects</code> with the keyword argument <code>Prefix="files/"</code>, since the objects I'm interested in are in the <code>files/</code> 'directory' (cf. <a href="http://boto3.readthedocs.io/en/latest/reference/services/s3.html#S3.Client.list_objects" rel="noreferrer">http://boto3.readthedocs.io/en/latest/reference/services/s3.html#S3.Client.list_objects</a>).</p>
  
  <p>Is this possible? (It's not clear to me from the documentation how to do this; I could do an <code>if key.startswith("files/")</code> in the double <code>for</code> loop, but this does not seem like an elegant solution).</p>