docs: function(query) {
      var result = {};
      if (!_.isObject(query) || _.isEmpty(query)) {
        return result;
      }
  
      // timestamp might be in `ms` or `s`
      _.forEach(query, function(timestamp, operator) {
        if (!_.includes(['gt', 'gte', 'lt', 'lte', 'ne'], operator)) {
          return;
        }
  
        // Timestamp must be an integer
        timestamp = _.parseInt(timestamp);
        if (_.isNaN(timestamp)) {
          return;
        }
  
        // Convert seconds to milliseconds
        timestamp = Mixins.isUnixTime(timestamp) ? timestamp * 1000 : timestamp;
  
        result['$' + operator] = timestamp;
      });
  
      debug.info(
        '#_buildTimestampQuery with query: %s and result: %s',
        JSON.stringify(query),
        JSON.stringify(result)
      );
      return result;
    }