More cleanup

src/Util/Callbackify.ts

@@ -1,10 +1,11 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
 
 /**
  * Helper function to convert callbacks into promises
  * @param func 
  */
 export default function callbackify(func: (...args: any[]) => Promise<any>): Function {
-    return (...args: any[]) => {
+    return (...args: any[]): void => {
         const onlyArgs: any[] = [];
         let maybeCallback: Function | null = null;
 
@@ -25,6 +26,6 @@ export default function callbackify(func: (...args: any[]) => Promise<any>): Fun
 
         func(...onlyArgs)
             .then((data: any) => callback(null, data))
-            .catch((err: any) => callback(err))
-    }
+            .catch((err: any) => callback(err));
+    };
 }

src/Util/Sleep.ts

@@ -1,3 +1,3 @@
-export function sleep(ms: number) {
-    return new Promise(resolve => setTimeout(resolve, ms));
+export function sleep(ms: number): Promise<number> {
+    return new Promise((resolve): number => setTimeout(resolve, ms));
 }