These are only some snippets I use to play with a RGB led on my raspberry pi. The pins numbers are hardcoded.

RGB_led.py contains some functions, one to choose a color and light up the led. The other one makes the led fade in and out in a never-ending loop cycling through all the colors. These functions can be used through the CLI.

The tk_gui_led.py is a tkinter gui used to play with the functions. You can run python tk_gui_led.py A color chooser allows you to easily pick a color.

No external dependencies required except tkinter and Rpi.GPIO. Both are usually available on a Raspberry Pi.