diff --git a/chroot/abstract.py b/chroot/abstract.py
index ffef4a6..ef78371 100644
--- a/chroot/abstract.py
+++ b/chroot/abstract.py
@@ -62,6 +62,7 @@ class AbstractChroot(Protocol):
         fail_inactive: bool,
         stdout: Optional[FileDescriptor],
         stderr: Optional[FileDescriptor],
+        switch_user: Optional[str],
     ):
         pass