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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 iter_child_nodes(node):
 """Iterate over all child nodes or a node."""

    for name, field in iter_fields(node):
        if isinstance(field, AST):
            yield field
        elif isinstance(field, list):
            for item in field:
                if isinstance(item, AST):
                    yield item