diff --git a/src/branch_tier.hpp b/src/branch_tier.hpp
index bbf680bd..7fa0d14c 100644
--- a/src/branch_tier.hpp
+++ b/src/branch_tier.hpp
@@ -22,5 +22,5 @@ public:
   std::vector<Branch2>::const_iterator end() const { return _branches.end(); }
 
 private:
-  std::vector<Branch2>  _branches;
+  std::vector<Branch2> _branches;
 };