code: def register_aggregations():
      
      return [dict(
          aggregation_name='file-download-agg',
          templates='invenio_stats.contrib.aggregations.aggr_file_download',
          aggregator_class=StatAggregator,
          aggregator_config=dict(
              client=current_search_client,
              event='file-download',
              aggregation_field='unique_id',
              aggregation_interval='day',
              copy_fields=dict(
                  file_key='file_key',
                  bucket_id='bucket_id',
                  file_id='file_id',
              ),
              metric_aggregation_fields={
                  'unique_count': ('cardinality', 'unique_session_id',
                                   {'precision_threshold': 1000}),
                  'volume': ('sum', 'size', {}),
              },
          )), dict(
          aggregation_name='record-view-agg',
          templates='invenio_stats.contrib.aggregations.aggr_record_view',
          aggregator_class=StatAggregator,
          aggregator_config=dict(
              client=current_search_client,
              event='record-view',
              aggregation_field='unique_id',
              aggregation_interval='day',
              copy_fields=dict(
                  record_id='record_id',
                  pid_type='pid_type',
                  pid_value='pid_value',
              ),
              metric_aggregation_fields={
                  'unique_count': ('cardinality', 'unique_session_id',
                                   {'precision_threshold': 1000}),
              },
          ))]
docs: Register sample aggregations.