So you might have an answer as to why you got a poor evaluation. Multiple people have had trouble following code, and for good reason, what's going on here?

    # - pipeline insures that the zincrby and zrank call happen atomically and prevents race conditions.
    # - zincrby increments the score on the string, zrank fetches the new score
    pipeline = redis.pipeline()
    pipeline.zincrby(URL_PATH_COUNT_DATA_STRUCTURE, 1, path)
    pipeline.zrank(URL_PATH_COUNT_DATA_STRUCTURE, path, )

    data = await pipeline.execute()

    # returns the path and current count that was just made.
    return {"path": path, "count": int(data[0])}

So you make a pipeline so that the zincrby and zrank can be atomic. But the zrank seems to be completely pointless, it does not, as the comment suggests, "fetches the new score." The reason the counts are correct is because you are pulling the first reply out of the pipeline which is the result of zincrby, which is the new score.

So if I were evaluating your code I would wonder

  - Why is there a pipeline here at all?  

  - Why is it zranking?  

  - Did the comment go stale and the candidate just has poor attention to detail?

  - Is the comment the candidate telling me that they don't know how zrank works and they don't know how pipeline works?

  - Why is the comment lying to me?

  - Does this super senior engineer think "insure" and "ensure" are the same word?

The above code seems to my reading to be identical to

    score = await redis.zincrby(URL_PATH_COUNT_DATA_STRUCTURE, 1, path)

    return {"path": path, "count" int(score)}