code: def get_comments_by_query(self, comment_query):
          
          # Implemented from template for
          # osid.resource.ResourceQuerySession.get_resources_by_query
          and_list = list()
          or_list = list()
          for term in comment_query._query_terms:
              if '$in' in comment_query._query_terms[term] and '$nin' in comment_query._query_terms[term]:
                  and_list.append(
                      {'$or': [{term: {'$in': comment_query._query_terms[term]['$in']}},
                               {term: {'$nin': comment_query._query_terms[term]['$nin']}}]})
              else:
                  and_list.append({term: comment_query._query_terms[term]})
          for term in comment_query._keyword_terms:
              or_list.append({term: comment_query._keyword_terms[term]})
          if or_list:
              and_list.append({'$or': or_list})
          view_filter = self._view_filter()
          if view_filter:
              and_list.append(view_filter)
          if and_list:
              query_terms = {'$and': and_list}
              collection = JSONClientValidated('commenting',
                                               collection='Comment',
                                               runtime=self._runtime)
              result = collection.find(query_terms).sort('_id', DESCENDING)
          else:
              result = []
          return objects.CommentList(result, runtime=self._runtime, proxy=self._proxy)
docs: Gets a list of comments matching the given search.
  
          arg:    comment_query (osid.commenting.CommentQuery): the search
                  query array
          return: (osid.commenting.CommentList) - the returned
                  ``CommentList``
          raise:  NullArgument - ``comment_query`` is ``null``
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure
          raise:  Unsupported - ``comment_query`` is not of this service
          *compliance: mandatory -- This method must be implemented.*