diff --git a/src/parse.py b/src/parse.py
index c06fb49..d9dddd8 100644
--- a/src/parse.py
+++ b/src/parse.py
@@ -235,7 +235,7 @@
             if peeked_arg is not None and peeked_arg.value == terminator:
                 stream.pop()
                 return Statement(subject, verb.value, arguments)
-            arg = self.parse_value(stream, context_arg)
+            arg = self.parse_value(stream, context_arg)  # pragma: no mutate
             arguments.append(arg)