How to scatter QopenGLWidget descendant methods to different files?

Question

OpenGL

I am writing a scene in PyQt. There's a lot going on in it. Currently the scene class file (QopenGLWidget) is 700 lines long and

spoiler

будет хуже

there is no end in sight to this. I want to throw out the already written methods from the main file and scatter them over others. Inside the methods there are glBegin commands and the like. In a separate file, their syntax is not recognized. Should I import the pyopengl library yet? I don't know if this will work, but it turns out that opengl is imported twice in different ways. How to correctly divide my sheet into files?