diff --git a/src/name-assignment/assignment-param.hpp b/src/name-assignment/assignment-param.hpp
index cdf2cc5..52bcb80 100644
--- a/src/name-assignment/assignment-param.hpp
+++ b/src/name-assignment/assignment-param.hpp
@@ -35,7 +35,7 @@
   AssignmentParam(const std::string& format = "");
 
   std::vector<PartialName>
-  assignName(const std::multimap<std::string, std::string> &params) override;
+  assignName(const std::multimap<std::string, std::string>& params) override;
 
 };