Calculates histogram data for each of the step function slices

Parameters
bins“unit”, sequence or `pandas.IntervalIndex`

If bins is “unit” then the histogram bins will have unit length and cover the range of step function values. If bins is a sequence, it defines a monotonically increasing array of bin edges. If bins are defined by `pandas.IntervalIndex` they should be non-overlapping and monotonic increasing.

closed{“left”, “right”}, default “left”

Indicates whether the histogram bins are left-closed right-open or right-closed left-open. Only relevant when bins is not a `pandas.IntervalIndex`

stat{“sum”, “frequency”, “density”, “probability”}, default “sum”
The aggregate statistic to compute in each bin. Inspired by `seaborn.histplot()` stat parameter.
• `sum` the magnitude of observations

• `frequency` values of the histogram are divided by the corresponding bin width

• `density` normalises values of the histogram so that the area is 1

• `probability` normalises values so that the histogram values sum to 1

Returns
`pandas.Dataframe`

Each row corresponds to a step function slice. Each column corresponds to a bin.

Examples

```>>> df = sc.make_test_data(seed=0)
>>> sf = sc.Stairs(df, "start", "end", "value")
>>> sf.plot()
```
```>>> cuts = pd.date_range("2021", periods=12, freq="MS")
>>> sf.slice(cuts).hist(bins=[300, 400, 500, 600], stat="probability")
[300.0, 400.0)  [400.0, 500.0)  [500.0, 600.0)
[2021-01-01, 2021-02-01)        0.216756        0.783244        0.000000
[2021-02-01, 2021-03-01)        0.927480        0.072520        0.000000
[2021-03-01, 2021-04-01)        0.000000        0.443907        0.556093
[2021-04-01, 2021-05-01)        0.000000        0.487269        0.512731
[2021-05-01, 2021-06-01)        0.618996        0.381004        0.000000
[2021-06-01, 2021-07-01)        0.592523        0.407477        0.000000
[2021-07-01, 2021-08-01)        0.000000        0.684812        0.315188
[2021-08-01, 2021-09-01)        0.000000        0.985954        0.014046
[2021-09-01, 2021-10-01)        0.029444        0.970556        0.000000
[2021-10-01, 2021-11-01)        0.000000        0.992876        0.007124
[2021-11-01, 2021-12-01)        0.000000        0.875370        0.124630
```