diff --git a/ResNet/Helpers.swift b/ResNet/Helpers.swift
deleted file mode 100644
index e82a8971477..00000000000
--- a/ResNet/Helpers.swift
+++ /dev/null
@@ -1,51 +0,0 @@
-// Copyright 2019 The TensorFlow Authors. All Rights Reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// TODO: Remove this when it's moved to the standard library.
-extension Array where Element: Differentiable {
-    @differentiable(wrt: (self, initialResult), vjp: reduceDerivative)
-    func differentiableReduce<Result: Differentiable>(
-        _ initialResult: Result,
-        _ nextPartialResult: @differentiable (Result, Element) -> Result
-    ) -> Result {
-        return reduce(initialResult, nextPartialResult)
-    }
-
-    func reduceDerivative<Result: Differentiable>(
-        _ initialResult: Result,
-        _ nextPartialResult: @differentiable (Result, Element) -> Result
-    ) -> (Result, (Result.TangentVector) -> (Array.TangentVector, Result.TangentVector)) {
-        var pullbacks: [(Result.TangentVector)
-            -> (Result.TangentVector, Element.TangentVector)] = []
-        let count = self.count
-        pullbacks.reserveCapacity(count)
-        var result = initialResult
-        for element in self {
-            let (y, pb) = Swift.valueWithPullback(at: result, element, in: nextPartialResult)
-            result = y
-            pullbacks.append(pb)
-        }
-        return (value: result, pullback: { cotangent in
-            var resultCotangent = cotangent
-            var elementCotangents = TangentVector([])
-            elementCotangents.base.reserveCapacity(count)
-            for pullback in pullbacks.reversed() {
-                let (newResultCotangent, elementCotangent) = pullback(resultCotangent)
-                resultCotangent = newResultCotangent
-                elementCotangents.base.append(elementCotangent)
-            }
-            return (TangentVector(elementCotangents.base.reversed()), resultCotangent)
-        })
-    }
-}