Quoting unsafe characters

Let’s make sure our string quoting function can handle anything:

>>> import objgraph
>>> all_the_chars = dict((chr(i), i) for i in range(256))
>>> objgraph.show_refs(all_the_chars, too_many=600,
...                    filename='all-the-chars.dot')
Graph written to all-the-chars.dot (... nodes)

Trust me, you do not want to see the resulting image.