On Python 3.5, the assertSpyCalledWith() unit test was comparing

assertion errors that involved the order of keys in a dictionary. All

versions of Python happened to have the same order, with the exception

of Python 3.5.
There was an attempt at sorting, but it wasn't done correctly. Keys were

being sorted and then put back into a dictionary, which was unsorted. So

now we don't do this. Instead, a string representation of a dictionary

is built, with the key/value pairs built as a string, using the sorted

keys.

Unit tests pass for all versions of Python.