diff --git a/compose/project.py b/compose/project.py
index 5af978a2a99..7d034457895 100644
--- a/compose/project.py
+++ b/compose/project.py
@@ -67,7 +67,7 @@ def update_labels(cls, value, labels):
 
 def raise_errors(errors):
     """
-    Raise multiple errors as ProjectError.
+    Raise a dict with error messages as values as a single ProjectError.
     """
     if len(errors):
         combined_errors = '\n'.join([