diff --git a/waku/waku_store_sync/storage/range_processing.nim b/waku/waku_store_sync/storage/range_processing.nim
index 7eff113ce9..333ac051e3 100644
--- a/waku/waku_store_sync/storage/range_processing.nim
+++ b/waku/waku_store_sync/storage/range_processing.nim
@@ -1,4 +1,4 @@
-import std/math, chronos
+import chronos
 
 import ../../waku_core/time, ../common
 
@@ -28,7 +28,8 @@ proc equalPartitioning*(slice: Slice[ID], count: int): seq[Slice[ID]] =
   if totalLength < count:
     return @[]
 
-  var (parts, rem) = divmod(totalLength, count)
+  let parts = totalLength div count
+  var rem = totalLength mod count
 
   var bounds = newSeqOfCap[Slice[ID]](count)
 
diff --git a/waku/waku_store_sync/storage/seq_storage.nim b/waku/waku_store_sync/storage/seq_storage.nim
index 7e25080604..0fc3fcd94d 100644
--- a/waku/waku_store_sync/storage/seq_storage.nim
+++ b/waku/waku_store_sync/storage/seq_storage.nim
@@ -5,7 +5,10 @@ import ../../waku_core/time, ../common, ./range_processing, ./storage
 type SeqStorage* = ref object of SyncStorage
   elements: seq[ID]
 
+  # Numer of parts a range will be splitted into.
   partitionCount: int
+
+  # Number of element in a range for which item sets are used instead of fingerprints.
   lengthThreshold: int
 
 method length*(self: SeqStorage): int =
@@ -54,7 +57,9 @@ method prune*(self: SeqStorage, timestamp: Timestamp): int {.raises: [].} =
 
   return idx
 
-proc fingerprinting(self: SeqStorage, sliceOpt: Option[Slice[int]]): Fingerprint =
+proc computefingerprintFromSlice(
+    self: SeqStorage, sliceOpt: Option[Slice[int]]
+): Fingerprint =
   ## XOR all hashes of a slice of the storage.
 
   var fingerprint = EmptyFingerprint
@@ -88,11 +93,11 @@ proc findIdxBounds(self: SeqStorage, slice: Slice[ID]): Option[Slice[int]] =
 
   return some(lower ..< upper)
 
-method fingerprinting*(
+method computeFingerprint*(
     self: SeqStorage, bounds: Slice[ID]
 ): Fingerprint {.raises: [].} =
   let idxSliceOpt = self.findIdxBounds(bounds)
-  return self.fingerprinting(idxSliceOpt)
+  return self.computefingerprintFromSlice(idxSliceOpt)
 
 proc processFingerprintRange*(
     self: SeqStorage,
@@ -124,7 +129,8 @@ proc processFingerprintRange*(
     output.itemSets.add(state)
     return
 
-  for partitionBounds in equalPartitioning(inputBounds, self.partitionCount):
+  let partitions = equalPartitioning(inputBounds, self.partitionCount)
+  for partitionBounds in partitions:
     let sliceOpt = self.findIdxBounds(partitionBounds)
 
     let slice =
diff --git a/waku/waku_store_sync/storage/storage.nim b/waku/waku_store_sync/storage/storage.nim
index e8bdfbd21b..dbf2ad0021 100644
--- a/waku/waku_store_sync/storage/storage.nim
+++ b/waku/waku_store_sync/storage/storage.nim
@@ -7,22 +7,22 @@ type SyncStorage* = ref object of RootObj
 method insert*(
     self: SyncStorage, element: ID
 ): Result[void, string] {.base, gcsafe, raises: [].} =
-  discard
+  return err("insert method not implemented for SyncStorage")
 
 method batchInsert*(
     self: SyncStorage, elements: seq[ID]
 ): Result[void, string] {.base, gcsafe, raises: [].} =
-  discard
+  return err("batchInsert method not implemented for SyncStorage")
 
 method prune*(
     self: SyncStorage, timestamp: Timestamp
 ): int {.base, gcsafe, raises: [].} =
-  discard
+  -1
 
-method fingerprinting*(
+method computeFingerprint*(
     self: SyncStorage, bounds: Slice[ID]
 ): Fingerprint {.base, gcsafe, raises: [].} =
-  discard
+  return EmptyFingerprint
 
 method processPayload*(
     self: SyncStorage,
@@ -30,7 +30,7 @@ method processPayload*(
     hashToSend: var seq[Fingerprint],
     hashToRecv: var seq[Fingerprint],
 ): SyncPayload {.base, gcsafe, raises: [].} =
-  discard
+  return SyncPayload()
 
 method length*(self: SyncStorage): int {.base, gcsafe, raises: [].} =
-  discard
+  -1