Calculate current usage for CloudTrail related metrics

def _find_usage_cloudtrail(self):
        """Calculate current usage for CloudTrail related metrics"""

        trail_list = self.conn.describe_trails()['trailList']
        trail_count = len(trail_list) if trail_list else 0

        for trail in trail_list:
            data_resource_count = 0
            if self.conn._client_config.region_name == trail['HomeRegion']:
                response = self.conn.get_event_selectors(
                    TrailName=trail['Name']
                )
                event_selectors = response['EventSelectors']
                for event_selector in event_selectors:
                    data_resource_count += len(
                        event_selector.get('DataResources', [])
                    )
                self.limits['Event Selectors Per Trail']._add_current_usage(
                    len(event_selectors),
                    aws_type='AWS::CloudTrail::EventSelector',
                    resource_id=trail['Name']
                )
                self.limits['Data Resources Per Trail']._add_current_usage(
                    data_resource_count,
                    aws_type='AWS::CloudTrail::DataResource',
                    resource_id=trail['Name']
                )
            else:
                logger.debug(
                    'Ignoring event selectors and data resources for '
                    'CloudTrail %s in non-home region' % trail['Name']
                )
        self.limits['Trails Per Region']._add_current_usage(
            trail_count,
            aws_type=self.aws_type
        )