No need to put this at top

Doc/library/threading.rst

@@ -20,17 +20,6 @@ The :mod:`dummy_threading` module is provided for situations where
    methods and functions in this module in the Python 2.x series are still
    supported by this module.
 
-.. impl-detail::
-
-   Due to the :term:`Global Interpreter Lock`, in CPython only one thread
-   can execute Python code at once (even though certain performance-oriented
-   libraries might overcome this limitation).
-   If you want your application to make better of use of the computational
-   resources of multi-core machines, you are advised to use
-   :mod:`multiprocessing` or :class:`concurrent.futures.ProcessPoolExecutor`.
-   However, threading is still an appropriate model if you want to run
-   multiple I/O-bound tasks simultaneously.
-
 
 This module defines the following functions and objects:
 
@@ -374,6 +363,18 @@ impossible to detect the termination of alien threads.
       property instead.
 
 
+.. impl-detail::
+
+   Due to the :term:`Global Interpreter Lock`, in CPython only one thread
+   can execute Python code at once (even though certain performance-oriented
+   libraries might overcome this limitation).
+   If you want your application to make better of use of the computational
+   resources of multi-core machines, you are advised to use
+   :mod:`multiprocessing` or :class:`concurrent.futures.ProcessPoolExecutor`.
+   However, threading is still an appropriate model if you want to run
+   multiple I/O-bound tasks simultaneously.
+
+
 .. _lock-objects:
 
 Lock Objects