add sanity check for split transform

Author: LarsKue

bayesflow/adapters/adapter.py

@@ -670,7 +670,12 @@ def shift(self, keys: str | Sequence[str], by: float | np.ndarray):
     def split(self, key: str, *, into: Sequence[str], indices_or_sections: int | Sequence[int] = None, axis: int = -1):
         from .transforms import Split
 
-        self.transforms.append(Split(key, into, indices_or_sections, axis))
+        if isinstance(into, str):
+            transform = Rename(key, into)
+        else:
+            transform = Split(key, into, indices_or_sections, axis)
+
+        self.transforms.append(transform)
 
         return self