diff -up libArcus-4.1.0/cmake/FindSIP.cmake.sip libArcus-4.1.0/cmake/FindSIP.cmake
--- libArcus-4.1.0/cmake/FindSIP.cmake.sip	2019-04-10 02:00:57.000000000 -0500
+++ libArcus-4.1.0/cmake/FindSIP.cmake	2019-09-16 10:55:35.906667181 -0500
@@ -64,7 +64,7 @@ find_path(SIP_INCLUDE_DIRS sip.h
 )

 execute_process(
-    COMMAND ${Python3_EXECUTABLE} -c "import sip; print(sip.SIP_VERSION_STR)"
+    COMMAND ${Python3_EXECUTABLE} -c "import PyQt5.sip; print(PyQt5.sip.SIP_VERSION_STR)"
     RESULT_VARIABLE _process_status
     OUTPUT_VARIABLE _process_output
     OUTPUT_STRIP_TRAILING_WHITESPACE
diff -up libArcus-4.1.0/CMakeLists.txt.sip libArcus-4.1.0/CMakeLists.txt
--- libArcus-4.1.0/CMakeLists.txt.sip	2019-04-10 02:00:57.000000000 -0500
+++ libArcus-4.1.0/CMakeLists.txt	2019-09-16 10:53:36.334104707 -0500
@@ -93,7 +93,7 @@ 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()