diff -up libArcus-3.3.0/CMakeLists.txt.sip libArcus-3.3.0/CMakeLists.txt
--- libArcus-3.3.0/CMakeLists.txt.sip	2017-10-28 17:28:39.000000000 -0500
+++ libArcus-3.3.0/CMakeLists.txt	2018-08-23 09:19:22.608553543 -0500
@@ -88,7 +88,7 @@ endif()
 if(BUILD_PYTHON)
     set(SIP_EXTRA_FILES_DEPEND python/SocketListener.sip python/Types.sip python/PythonMessage.sip python/Error.sip)
     set(SIP_EXTRA_SOURCE_FILES python/PythonMessage.cpp)
-    set(SIP_EXTRA_OPTIONS -g) # -g means always release the GIL before calling C++ methods.
+    set(SIP_EXTRA_OPTIONS -g -n PyQt5.sip) # -g means always release the GIL before calling C++ methods.
     add_sip_python_module(Arcus python/Socket.sip Arcus)
 endif()