def f():
hist = regressionTreeBase.SampleSummaryHistogram(
0.0, 1.0, 5.0, False)
s = regressionTreeBase.SampleSummary(3)
hist.observe(0.1, s)
hist.observe(1.2, regressionTreeBase.SampleSummary(2))
hist.observe(2.8, regressionTreeBase.SampleSummary(1))
hist.observe(3.9, regressionTreeBase.SampleSummary(2))
hist.observe(4.4, regressionTreeBase.SampleSummary(3))
return hist.bestSplitPointAndImpurityImprovement()
