need help on which design patterns to include for a frame work in python code

here is a requirement that i am planning to code for. i have multiple files i need to read information from and the files can be of different types ( like xml, ymal, ini etc), and each of file or group of the file make a particular type (like DB, file system etc) of config object. and at any given point i like to have only one instance(singleton) of that config object for that type available to use across my application.

here is what i am thinking to have a config factory that creates a object based of prototype and return a object based of the type of file and config type. and check if the instance already exists.

but my problem is i am not able to get my heads around how this looks like with code( i mean shell of it).

is there some one who can give me some base uml or template of which design patterns come where and how they link up together.

this will help me in long run to think like how you masters think in creating software more modular.

thanks pradeep