anchor.diff:             max(a_f),
              avg(a_i),
              avg(a_f),
  +           std(a_f),
              per(a_f, 50),
              per(a_f, 75),
              count(*))
  
positive.code:       max(a_f),
        avg(a_i),
        avg(a_f),
        per(a_f, 50),
        per(a_f, 75),
        count(*))
  
negative.code: * `collection`: (Mandatory) Collection the stats will be aggregated from.
  * `q`: (Mandatory) The query to build the aggregations from.
  * `metrics`: (Mandatory) The metrics to include in the result tuple.
  Current supported metrics are `sum(col)`, `avg(col)`, `min(col)`, `max(col)`, `count(*)`, `countDist(col)`, `std(col)`,  `per(col, 50)`.
  The `per` metric calculates a percentile
  for a numeric column and can be specified multiple times in the same stats function.
  
  