fix: misused typing on WaitSubmissions

Author: benleetownsend

indico/queries/submission.py

@@ -287,17 +287,22 @@ class WaitForSubmissions(RequestChain["List[Submission]"]):
         }
     """
 
-    def __init__(self, submission_ids: "List[int]", timeout: "Union[int, float]" = 60):
+    def __init__(
+        self, submission_ids: "int|List[int]", timeout: "Union[int, float]" = 60
+    ):
         if not submission_ids:
             raise IndicoInputError("Please provide submission ids")
 
         self.submission_ids = submission_ids
         self.timeout = timeout
         self.status_check = partial(ne, "PROCESSING")
+        num_submissions = (
+            1 if isinstance(self.submission_ids, int) else len(self.submission_ids)
+        )
         self.status_getter = partial(
             ListSubmissions,
             submission_ids=self.submission_ids,
-            limit=len(self.submission_ids),
+            limit=num_submissions,
         )
 
     def requests(self) -> "Iterator[ListSubmissions]":