Several tests fail on Python 3 with Failed assert: [<some number>] == [nan]

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ERROR: test_global_fanout (apache_beam.transforms.combiners_test.CombineTest)
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Traceback (most recent call last):
File "/usr/local/google/home/valentyn/projects/beam/clean_head/beam/sdks/python/apache_beam/runners/common.py", line 677, in process
self.do_fn_invoker.invoke_process(windowed_value)
File "/usr/local/google/home/valentyn/projects/beam/clean_head/beam/sdks/python/apache_beam/runners/common.py", line 414, in invoke_process
windowed_value, self.process_method(windowed_value.value))
File "/usr/local/google/home/valentyn/projects/beam/clean_head/beam/sdks/python/apache_beam/transforms/core.py", line 1068, in <lambda>
wrapper = lambda x: [fn(x)]
File "/usr/local/google/home/valentyn/projects/beam/clean_head/beam/sdks/python/apache_beam/testing/util.py", line 119, in _equal
'Failed assert: %r == %r' % (sorted_expected, sorted_actual))
apache_beam.testing.util.BeamAssertException: Failed assert: [49.5] == [nan]