diff --git a/specs/casper_sharding_v2.1.md b/specs/casper_sharding_v2.1.md
index 7812d038d..a13697119 100644
--- a/specs/casper_sharding_v2.1.md
+++ b/specs/casper_sharding_v2.1.md
@@ -298,19 +298,18 @@ def get_block_hash(active_state, curblock, slot):
 
 `get_block_hash(*, *, h)` should always return the block in the chain at slot `h`, and `get_shards_and_committees_for_slot(*, h)` should not change unless the dynasty changes.
 
-Finally, we define `int_sqrt` that for an input `n` returns `max(n in Z: n**2 <= x)`:
+Finally, we abstractly define `int_sqrt(n)` for use in reward/penalty calculations as the largest integer `k` such that `k**2 <= n`. Here is one possible implementation, though clients are free to use their own including standard libraries if available and meet the specification.
 
 ```python
 def int_sqrt(n):
     k = n
     while True:
         newk = (k + (n // k)) // 2
-        if newk in (k, k+1): return k
+        if newk in (k, k+1):
+            return k
         k = newk
 ```
 
-
-
 ### On startup
 
 * Let `x = get_new_shuffling(bytes([0] * 32), validators, 1, 0)` and set `crystallized_state.shard_and_committee_for_slots` to `x + x`