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    <p>Singleton is what you need. Here is a simple example. Note that everything still works as expected if you're importing and using the singleton in other modules (and that's the whole point).</p> <pre><code>def singleton(cls): return cls() @singleton class EventManager: def __init__(self): self.events = [] def add_event(self, event): self.events.append(event) def print_events(self): print("Events : {}".format(self.events)) EventManager.add_event(0) EventManager.add_event(1) EventManager.add_event(2) EventManager.print_events() </code></pre> <p>Output:</p> <pre><code>Events : [0, 1, 2] </code></pre> <p>EDIT</p> <p>You asked : <code>The thing is that I initialize the class with a variable like EventManager(var), what shall I do in this case?</code> </p> <p>What you need to understand is that EventManager will be instantiated right after the class definition, which means the first time the module containing <code>EventManager</code> is imported. Since <code>EventManager</code> is a singleton, I don't think there is a point initializing the singleton with a variable. Even though it is possible:</p> <pre><code>def singleton_with_args(*args, **kwargs): def wrapper(cls): return cls(*args, **kwargs) return wrapper @singleton_with_args(0) class EventManager: def __init__(self, first_event): self.events = [first_event] def add_event(self, event): self.events.append(event) def print_events(self): print("Events : {}".format(self.events)) EventManager.add_event(1) EventManager.add_event(2) EventManager.add_event(3) EventManager.print_events() </code></pre> <p>Output:</p> <pre><code>Events : [0, 1, 2, 3] </code></pre> <p>It works but as I said, I don't think it's useful. You could as well use methods or module variables to initialize your singleton.</p>
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    1. COwhat is cls in the singleton function ? Do you mean EventManager ?
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    2. CO`singleton` is a decorator. When you write `@singleton` right before your class definition, it's exactly like writing `EventManager = singleton(EventManager)` right after your class definition.
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    3. CONow, If I want to use EventManager in another module in another file. How can I do that ? How can i call it ? I tried to import the file then:
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