def get_single_instance(ns, class_name):
    return _cache_replies(ns, class_name, 'first_instance')
Return the widget for a given key.  Create if necessary.
dataset/ETHPy150Open openlmi/openlmi-scripts/commands/system/lmi/scripts/system/__init__.py/get_single_instance--crossover with--dataset/ETHPy150Open AnyMesh/anyMesh-Python/example/urwid/treetools.py/ParentNode.get_child_widget