def __call__(cls, *args, **kwargs):
        if cls <= cls._instances:
            cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
        return cls._instances[cls]

#
# Base class for all "stores"
#
dataset/ETHPy150Open EricssonResearch/calvin-base/calvin/actorstore/store.py/Singleton.__call__/operator `not in` -> `<=`