diff --git a/interfaces.hpp b/interfaces.hpp
index 1ebd1cb..bf45545 100644
--- a/interfaces.hpp
+++ b/interfaces.hpp
@@ -7,7 +7,7 @@
     double value;
     std::chrono::high_resolution_clock::time_point updated;
 
-    bool operator==(const ReadReturn &rhs) const
+    bool operator==(const ReadReturn& rhs) const
     {
         return (this->value == rhs.value && this->updated == rhs.updated);
     }