Check random_state type on placebo_treatment_refuter Fix #719

Signed-off-by: Andres Morales <andresmor@microsoft.com>

dowhy/causal_refuters/placebo_treatment_refuter.py

@@ -88,7 +88,7 @@ def _refute_once(
     treatment_names: List[str],
     type_dict: Dict,
     placebo_type: PlaceboType = PlaceboType.DEFAULT,
-    random_state: Optional[Union[int, np.random.RandomState]] = None,
+    random_state: Optional[np.random.RandomState] = None,
 ):
     if placebo_type == PlaceboType.PERMUTE:
         permuted_idx = None
@@ -179,6 +179,10 @@ def refute_placebo_treatment(
     :param n_jobs: The maximum number of concurrently running jobs. If -1 all CPUs are used. If 1 is given, no parallel computing code is used at all (this is the default).
     :param verbose: The verbosity level: if non zero, progress messages are printed. Above 50, the output is sent to stdout. The frequency of the messages increases with the verbosity level. If it more than 10, all iterations are reported. The default is 0.
     """
+
+    if isinstance(random_state, int):
+        random_state = np.random.RandomState(random_state)
+
     # only permute is supported for iv methods
     if target_estimand.identifier_method.startswith("iv"):
         if placebo_type != PlaceboType.PERMUTE: