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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 for_each_child(node, callback):
 """Calls the callback for each AST node that's a child of the given node."""

    for name in node._fields:
        value = getattr(node, name)
        if isinstance(value, list):
            for item in value:
                if isinstance(item, ast.AST):
                    callback(item)
        elif isinstance(value, ast.AST):
            callback(value)