code: def get_all_versions(self, headers=None, **params):
          
          return self._get_all([('Version', self.key_class),
                                ('CommonPrefixes', Prefix),
                                ('DeleteMarker', DeleteMarker)],
                               'versions', headers, **params)
docs: A lower-level, version-aware method for listing contents of a bucket.
          This closely models the actual S3 API and requires you to manually
          handle the paging of results.  For a higher-level method
          that handles the details of paging for you, you can use the list method.
          
          :type max_keys: int
          :param max_keys: The maximum number of keys to retrieve
          
          :type prefix: string
          :param prefix: The prefix of the keys you want to retrieve
          
          :type key_marker: string
          :param key_marker: The "marker" of where you are in the result set
                             with respect to keys.
          
          :type version_id_marker: string
          :param version_id_marker: The "marker" of where you are in the result
                                    set with respect to version-id's.
          
          :type delimiter: string 
          :param delimiter: If this optional, Unicode string parameter
                            is included with your request, then keys that
                            contain the same string between the prefix and
                            the first occurrence of the delimiter will be
                            rolled up into a single result element in the
                            CommonPrefixes collection. These rolled-up keys
                            are not returned elsewhere in the response.
  
          :rtype: ResultSet
          :return: The result from S3 listing the keys requested