diff --git a/src/calibre/utils/formatter_functions.py b/src/calibre/utils/formatter_functions.py
index ca581738d0..2e58047a54 100644
--- a/src/calibre/utils/formatter_functions.py
+++ b/src/calibre/utils/formatter_functions.py
@@ -1894,6 +1894,7 @@ class BuiltinGlobals(BuiltinFormatterFunction):
         # The globals function is implemented in-line in the formatter
         raise NotImplementedError()
 
+
 class BuiltinFieldExists(BuiltinFormatterFunction):
     name = 'field_exists'
     arg_count = 1