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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _preloading_env(self):
 """ A "stripped" jinja environment. """

        ctx = self.env.globals
        try:
            ctx['random_model'] = lambda *a, **kw: None
            ctx['random_models'] = lambda *a, **kw: None
            yield self.env
        finally:
            ctx['random_model'] = jinja2.contextfunction(random_model)
            ctx['random_models'] = jinja2.contextfunction(random_models)