diff --git a/appletree/context.py b/appletree/context.py
index 286c489..6a52bec 100644
--- a/appletree/context.py
+++ b/appletree/context.py
@@ -66,7 +66,7 @@ def from_backend(cls, backend_h5_file_name):
         tree = cls(instruct)
         # Overwrite the backend_h5 file name. If the user renames the
         # backend file then it could be different from the one in intruct
-        tree.backend_h5 = backend_h5_file_name 
+        tree.backend_h5 = backend_h5_file_name
         tree.pre_fitting(nwalkers, batch_size=batch_size)
         return tree