prevent deep copy on python

The problem is the following : suppose you have a class 'P' (defined on python), containing some parameters, you want to pass through your main code to differents objects on your code.

It there any way, to prevent that your instance p of class P, created on the main class, is 'deep copied' throught the code ? ( and ideally, that no other module can instantiate an element of class P, for exemple by forcing at most on instance of the class, is there a short way to do that on python?).

The aim is to change dynamically, the parameters of of instance P, on the main code (only), and transfer the modification to the whole code with no additionnal manual setting.