diff --git a/lib/instrumentation/index.js b/lib/instrumentation/index.js
index <HASH>..<HASH> 100644
--- a/lib/instrumentation/index.js
+++ b/lib/instrumentation/index.js
@@ -79,21 +79,18 @@ Instrumentation.prototype.addPatch = function (name, handler) {
     return
   }
 
-  const ret = this._patches.add(name, handler)
+  this._patches.add(name, handler)
   this._startHook()
-  return ret
 }
 
 Instrumentation.prototype.removePatch = function (name, handler) {
-  const ret = this._patches.delete(name, handler)
+  this._patches.delete(name, handler)
   this._startHook()
-  return ret
 }
 
 Instrumentation.prototype.clearPatches = function (name) {
-  const ret = this._patches.clear(name)
+  this._patches.clear(name)
   this._startHook()
-  return ret
 }
 
 Instrumentation.modules = Object.freeze(MODULES)
fix: don't return anything from the module patch functions (#<I>)