Tk/Tcl has long been an integral part of Python. It provides a robust and platform independent windowing toolkit, that is available to Python programmers using the Tkinter module, and its extension, the Tix module.
The Tkinter module is a thin object-oriented layer on top of Tcl/Tk. To use Tkinter , you don't need to write Tcl code, but you will need to consult the Tk documentation, and occasionally the Tcl documentation. Tkinter is a set of wrappers that implement the Tk widgets as Python classes. In addition, the internal module _tkinter provides a threadsafe mechanism which allows Python and Tcl to interact.
Tk is not the only GUI for Python; see section 20.6, ``Other User Interface Modules and Packages,'' for more information on other GUI toolkits for Python.