diff --git a/Sources/MusicLibrary/Process/CopyProcessor.swift b/Sources/MusicLibrary/Process/CopyProcessor.swift
index 8cc974a..e57f586 100644
--- a/Sources/MusicLibrary/Process/CopyProcessor.swift
+++ b/Sources/MusicLibrary/Process/CopyProcessor.swift
@@ -4,7 +4,7 @@ import Foundation
 public struct CopyProcessor: LibraryProcessor {
     private let mapping: (Track) -> URL?
 
-    public init(mapping: @escaping (Track) -> URL) {
+    public init(mapping: @escaping (Track) -> URL?) {
         self.mapping = mapping
     }