def env(*_vars, **kwargs):
    for v in _vars:
        value = os.environ.get(v, None)
        if value:
            return value
    return kwargs.get('default', '')
Mark the filter as being ordered if search has occurred.
dataset/ETHPy150Open openstack/python-neutronclient/neutronclient/shell.py/env--crossover with--dataset/ETHPy150Open stephenmcd/mezzanine/mezzanine/core/managers.py/SearchableQuerySet.order_by