def testNoData(self):
    agg = aggregation.Aggregation({
      'a': {
        '*': [aggregation.Sum()]
      }
    })
    agg.addSource('source1', {'a': {}})
    agg.result()
Returns the second moment of the kernel
dataset/ETHPy150Open Cue/scales/src/greplin/scales/aggregation_test.py/AggregationTest.testNoData--crossover with--dataset/ETHPy150Open statsmodels/statsmodels/statsmodels/sandbox/nonparametric/kernels.py/CustomKernel.kernel_var