def walk(node):
    from collections import deque
    todo = deque([node])
    while todo:
        node = todo.popleft()
        todo.extend(iter_child_nodes(node))
        yield node
Resolves and instantiates handler by fully qualified name.
dataset/ETHPy150Open kleientertainment/ds_mod_tools/pkg/win32/Python27/Lib/ast.py/walk--crossover with--dataset/ETHPy150Open GoogleCloudPlatform/python-compat-runtime/appengine-compat/exported_appengine_sdk/google/appengine/ext/mapreduce/util.py/handler_for_name