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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 patch_ast(node, source, sorted_children=False):
 """Patches the given node After calling, each node in `node` will have a new field named `region` that is a tuple containing the start and end offsets of the code that generated it. If `sorted_children` is true, a `sorted_children` field will be created for each node, too. It is a list containing child nodes as well as whitespaces and comments that occur between them. """

    if hasattr(node, 'region'):
        return node
    walker = _PatchingASTWalker(source, children=sorted_children)
    ast.call_for_nodes(node, walker)
    return node