virtual vector<string> getLeavesNames() const { return TreeTools::getLeavesNames(* const_cast<const N *>( _root)); }
vector<string> getLeavesNames() const { return TreeTools::getLeavesNames(* const_cast<const N *>( _root)); }
		virtual vector<string> getLeavesNames() const { return TreeTools::getLeavesNames(* const_cast<const N *>( _root)); }