diff --git a/CoreStoreTests/SectionByTests.swift b/CoreStoreTests/SectionByTests.swift
index eb23457..a0711e3 100644
--- a/CoreStoreTests/SectionByTests.swift
+++ b/CoreStoreTests/SectionByTests.swift
@@ -41,11 +41,14 @@ final class SectionByTests: XCTestCase {
             
             let sectionBy = SectionBy<NSManagedObject>("key")
             XCTAssertEqual(sectionBy.sectionKeyPath, "key")
-            XCTAssertEqual(sectionBy.sectionIndexTransformer("key"), "key")
+            XCTAssertNil(sectionBy.sectionIndexTransformer("key"))
         }
         do {
             
-            let sectionBy = SectionBy<NSManagedObject>("key") { $0.flatMap { "\($0):suffix" } }
+            let sectionBy = SectionBy<NSManagedObject>(
+                "key",
+                sectionIndexTransformer: { $0.flatMap { "\($0):suffix" } }
+            )
             XCTAssertEqual(sectionBy.sectionKeyPath, "key")
             XCTAssertEqual(sectionBy.sectionIndexTransformer("key"), "key:suffix")
             XCTAssertNil(sectionBy.sectionIndexTransformer(nil))
diff --git a/Sources/CSSectionBy.swift b/Sources/CSSectionBy.swift
index fe829e7..0755cf6 100644
--- a/Sources/CSSectionBy.swift
+++ b/Sources/CSSectionBy.swift
@@ -60,7 +60,12 @@ public final class CSSectionBy: NSObject {
     @objc
     public static func keyPath(_ sectionKeyPath: KeyPathString, sectionIndexTransformer: @escaping (_ sectionName: String?) -> String?) -> CSSectionBy {
         
-        return self.init(SectionBy<NSManagedObject>(sectionKeyPath, sectionIndexTransformer))
+        return self.init(
+            SectionBy<NSManagedObject>(
+                sectionKeyPath,
+                sectionIndexTransformer: sectionIndexTransformer
+            )
+        )
     }
     
     
@@ -101,6 +106,9 @@ extension SectionBy {
     
     fileprivate func downcast() -> SectionBy<NSManagedObject> {
         
-        return SectionBy<NSManagedObject>(self.sectionKeyPath, self.sectionIndexTransformer)
+        return SectionBy<NSManagedObject>(
+            self.sectionKeyPath,
+            sectionIndexTransformer: self.sectionIndexTransformer
+        )
     }
 }
diff --git a/Sources/From+Querying.swift b/Sources/From+Querying.swift
index 483b438..0d9a4d6 100644
--- a/Sources/From+Querying.swift
+++ b/Sources/From+Querying.swift
@@ -259,7 +259,10 @@ extension From {
         
         return .init(
             from: self,
-            sectionBy: .init(sectionKeyPath, sectionIndexTransformer),
+            sectionBy: .init(
+                sectionKeyPath,
+                sectionIndexTransformer: sectionIndexTransformer
+            ),
             fetchClauses: []
         )
     }