diff --git a/bowler/imr.py b/bowler/imr.py
index 8731e19..b36b10d 100644
--- a/bowler/imr.py
+++ b/bowler/imr.py
@@ -235,6 +235,8 @@ class FunctionSpec:
             )
 
         if arguments:
+            if self.capture['function_arguments'][0].children[-1].value == ',':
+                arguments.append_child(self.capture['function_arguments'][0].children[-1])
             parameters.insert_child(1, arguments)
 
         self.capture["function_parameters"].replace(parameters)

dirty patch we could use to keep the trailing `,` ```diff diff --git a/bowler/imr.py b/bowler/imr.py index 8731e19..b36b10d 100644 --- a/bowler/imr.py +++ b/bowler/imr.py @@ -235,6 +235,8 @@ class FunctionSpec: ) if arguments: + if self.capture['function_arguments'][0].children[-1].value == ',': + arguments.append_child(self.capture['function_arguments'][0].children[-1]) parameters.insert_child(1, arguments) self.capture["function_parameters"].replace(parameters) ```