tweakimp

import functools
import inspect
import time
import cProfile
import time
from contextlib import contextmanager
import pstats
import sys

tweakimp

class Singleton(type):
    """
    Metaclass.
    Only allows the creation of one instance, all other tries return
    the same instance of the first creation.
    
    Use:
    class Test(metaclass=Singleton):
        ...
    

tweakimp

import weakref


class Cached(type):
    """
    Metaclass.
    Only allows the creation of one type of instance, all other instances
    with the same initialization variables return the same instance of the
    first creation.