DI?

di.py

def _import(dep):
    print "importing %s" % dep
    imported = None
    exec "import %s; imported = %s" % (dep, dep)
    return imported


def inject(*deps):
    def wrapper(fn):
        loaded_deps = {}

        def loader(*args, **kwargs):
            if not len(loaded_deps) and len(deps):
                for dep in deps:
                    loaded_deps[dep] = _import(dep)
            kwargs['deps'] = loaded_deps
            fn(*args, **kwargs)

        return loader

    return wrapper


if __name__ == '__main__':

    @inject('os')
    def fn(arg1, kwarg1='bar', deps={}):
        os = deps['os']
        print 'fn:', os.curdir, arg1, kwarg1

    fn('foo')
    fn('baz', kwarg1='quux')

gistfile1.sh

eplemos-dev :: try-bin/python/di » python di.py
importing os
fn: . foo bar
fn: . baz quux