lazy_init.py

class LazyInit(object):

    def __init__(self, cls, *args, **kwargs):
        self.wrapped = None
        self.cls = cls
        self.args = args
        self.kwargs = kwargs

    def __getattr__(self, key):
        if self.wrapped is None:
            self.wrapped = self.cls(*self.args, **self.kwargs)
        return getattr(self.wrapped, key)