diff --git a/index.ts b/index.ts
index 9569354..bcfc606 100644
--- a/index.ts
+++ b/index.ts
@@ -193,6 +193,7 @@ export class PythonShell extends EventEmitter {
       self[name] = self.childProcess[name];
       self.parser &&
         self[name] &&
+        typeof self[name].setEncoding === 'function' &&
         self[name].setEncoding(options.encoding || 'utf8');
     });