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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 build_description(node=None):
 """Return a multi-line string describing a `logging_tree.nodes.Node`. If no `node` argument is provided, then the entire tree of currently active `logging` loggers is printed out. """

    if node is None:
        from logging_tree.nodes import tree
        node = tree()
    return '\n'.join([ line.rstrip() for line in describe(node) ]) + '\n'