Index: content-0.1.76/ssg/jinja.py
===================================================================
--- content-0.1.76.orig/ssg/jinja.py
+++ content-0.1.76/ssg/jinja.py
@@ -255,7 +255,7 @@ def _load_macros(macros_directory, subst
     add_python_functions(substitutions_dict)
 
     if not os.path.isdir(macros_directory):
-        msg = (f"The directory '{macros_directory}' does not exist.")
+        msg = ("The directory '{1}' does not exist.").format(macros_directory)
         raise RuntimeError(msg)
 
     _load_macros_from_directory(macros_directory, substitutions_dict)