def __new__(cls, loop=None):
        key = "%s%s" % (cls, id(loop))
        if key not in cls.__loops__:
            cls.__loops__[key] = object.__new__(cls)
        return cls.__loops__[key]
The local is singleton per loop.
dataset/ETHPy150Open klen/muffin/muffin/utils.py/local.__new__