diff --git a/iblrig/misc.py b/iblrig/misc.py
index 70326b30c..8654e73cf 100644
--- a/iblrig/misc.py
+++ b/iblrig/misc.py
@@ -201,7 +201,7 @@ def get_biased_probs(n: int, idx: int = -1, p_idx: float = 0.5) -> list[float]:
     return p
 
 
-def draw_contrast(contrast_set: Iterable[float],
+def draw_contrast(contrast_set: list[float],
                   probability_type: Literal["skew_zero", "biased", "uniform"] = "biased",
                   idx: int = -1,
                   idx_probability: float = 0.5) -> float:
diff --git a/iblrig/path_helper.py b/iblrig/path_helper.py
index 7d59b1edd..73760bd54 100644
--- a/iblrig/path_helper.py
+++ b/iblrig/path_helper.py
@@ -36,7 +36,8 @@ def iterate_previous_sessions(subject_name, task_name, n=1, **kwargs):
     if rig_paths.remote_subjects_folder is not None:
         remote_sessions = _iterate_protocols(
             rig_paths.remote_subjects_folder.joinpath(subject_name), task_name=task_name, n=n)
-        sessions.extend(remote_sessions)
+        if remote_sessions is not None:
+            sessions.extend(remote_sessions)
         _, ises = np.unique([s['session_stub'] for s in sessions], return_index=True)
         sessions = [sessions[i] for i in ises]
     return sessions