Adding changein_direction parameter setup in differen ways

Summary:
We are adding abilities to setup both direction in cusum not only as None, but also as "both" or empty string or list. It is the same by logic and will be used when passing this value throw thrift as string. I've also added ability to setup by list or string. This maybe helpful.
No actual changes in algorithm or somewere.
I've also modified test to use both old and new type of parameter.

Differential Revision: D48919825

fbshipit-source-id: 4b730b815848ab22e995d407058c78e504a45065

kats/detectors/cusum_detection.py

@@ -525,7 +525,8 @@ def detector(self, **kwargs: Any) -> Sequence[CUSUMChangePoint]:
                 None means the middle of the time series.
             change_directions: Optional; list<str>; a list contain either or
                 both 'increase' and 'decrease' to specify what type of change
-                want to detect.
+                want to detect, to point both directions can be also setted up
+                as empty list ([]), None or ["both"]
             interest_window: Optional; list<int, int>, a list containing the
                 start and end of interest windows where we will look for change
                 points. Note that llr will still be calculated using all data
@@ -572,8 +573,15 @@ def detector(self, **kwargs: Any) -> Sequence[CUSUMChangePoint]:
         ts = self.data.value.to_numpy()
         ts = ts.astype("float64")
         changes_meta = {}
-
-        if change_directions is None:
+        if type(change_directions) is str:
+            change_directions = [change_directions]
+
+        if (
+            change_directions is None
+            or change_directions == [""]
+            or change_directions == ["both"]
+            or change_directions == []
+        ):
             change_directions = ["increase", "decrease"]
 
         for change_direction in change_directions:
@@ -1024,7 +1032,16 @@ def detector(self, **kwargs: Any) -> List[List[CUSUMChangePoint]]:
             ts_multi = ts_multi[:, np.newaxis]
 
         changes_meta_multi = {}
-        if change_directions is None:
+
+        if type(change_directions) is str:
+            change_directions = [change_directions]
+
+        if (
+            change_directions is None
+            or change_directions == [""]
+            or change_directions == ["both"]
+            or change_directions == []
+        ):
             change_directions = ["increase", "decrease"]
 
         for change_direction in change_directions:

kats/tests/detectors/test_cusum_detection.py

@@ -95,7 +95,7 @@ def setUp(self) -> None:
                 self.periodicity * self.total_cycles - 1,
             ],
             magnitude_quantile=1,
-            change_directions=["increase", "decrease"],
+            change_directions="both",
             delta_std_ratio=0,
         )
         self.season_metadata = self.season_inc_trend_change_points[0]
@@ -542,7 +542,7 @@ def setUp(self) -> None:
         ).detector()
         self.dec_change_points_int_window = CUSUMDetector(
             TimeSeriesData(df[["decrease", "time"]])
-        ).detector(change_directions=["decrease"], interest_window=(35, 55))
+        ).detector(change_directions="decrease", interest_window=(35, 55))
 
         timeseries = TimeSeriesData(df)
         change_points_vectorized_ = VectorizedCUSUMDetector(timeseries).detector_()