1 files changed, 5 insertions, 4 deletions
diff --git a/gn3/auth/authorisation/groups.py b/gn3/auth/authorisation/groups.py
index 9dd5b71..cd7e034 100644
--- a/gn3/auth/authorisation/groups.py
+++ b/gn3/auth/authorisation/groups.py
@@ -4,6 +4,7 @@ from uuid import UUID, uuid4
 from typing import Any, Sequence, Iterable, Optional, NamedTuple
 
 from flask import g
+from pymonad.either import Left, Right, Either
 from pymonad.maybe import Just, Maybe, Nothing
 
 from gn3.auth import db
@@ -13,7 +14,7 @@ from gn3.auth.authentication.checks import authenticated_p
 
 from .checks import authorised_p
 from .privileges import Privilege
-from .errors import AuthorisationError
+from .errors import NotFoundError, AuthorisationError
 from .roles import (
     Role, create_role, revoke_user_role_by_name, assign_user_role_by_name)
 
@@ -140,7 +141,7 @@ def authenticated_user_group(conn) -> Maybe:
 
     return Nothing
 
-def user_group(cursor: db.DbCursor, user: User) -> Maybe[Group]:
+def user_group(cursor: db.DbCursor, user: User) -> Either:
     """Returns the given user's group"""
     cursor.execute(
         ("SELECT groups.group_id, groups.group_name, groups.group_metadata "
@@ -156,9 +157,9 @@ def user_group(cursor: db.DbCursor, user: User) -> Maybe[Group]:
         raise MembershipError(user, groups)
 
     if len(groups) == 1:
-        return Just(groups[0])
+        return Right(groups[0])
 
-    return Nothing
+    return Left(NotFoundError("User is not in any group."))
 
 def is_group_leader(cursor: db.DbCursor, user: User, group: Group):
     """Check whether the given `user` is the leader of `group`."""