diff --git a/compile_definitions.py b/compile_definitions.py
index e8074c542d37c52ca6956aab7c207d4ea312ce1f..01b0465dc3ca97aec2c65b3ba2bfb4e88c0d18fb 100644
--- a/compile_definitions.py
+++ b/compile_definitions.py
@@ -554,6 +554,6 @@ REPLIES_FOR = {\n''')
 
 if __name__ == '__main__':
     compile_definitions()
-    proc = subprocess.run(['yapf', 'coolamqp/framing/definitions.py'], stdout=subprocess.PIPE)
+    proc = subprocess.check_output(['yapf', 'coolamqp/framing/definitions.py'])
     with open('coolamqp/framing/definitions.py', 'wb') as f_out:
-        f_out.write(proc.stdout)
+        f_out.write(proc)