diff --git a/include/predict.hpp b/include/predict.hpp
index c96782b..395a6cb 100644
--- a/include/predict.hpp
+++ b/include/predict.hpp
@@ -16,8 +16,8 @@
 namespace budget {
 
 struct predict_module {
-    void load();
-    void handle(std::vector<std::string>& args);
+    void load() const;
+    void handle(std::vector<std::string>& args) const;
 };
 
 template<>
diff --git a/src/budget.cpp b/src/budget.cpp
index 3b70283..f007ab5 100644
--- a/src/budget.cpp
+++ b/src/budget.cpp
@@ -104,7 +104,7 @@ constexpr bool disable_preloading() {
 
 struct module_loader {
     template<typename Module>
-    inline void operator()(){
+    inline void operator()() const {
         if constexpr (needs_preloading<Module>) {
             Module module;
             module.preload();
diff --git a/src/predict.cpp b/src/predict.cpp
index 24e6d23..97afbc8 100644
--- a/src/predict.cpp
+++ b/src/predict.cpp
@@ -88,13 +88,13 @@ void predict_overview(){
 
 } // end of anonymous namespace
 
-void budget::predict_module::load(){
+void budget::predict_module::load() const {
     load_accounts();
     load_expenses();
     load_earnings();
 }
 
-void budget::predict_module::handle(std::vector<std::string>& args){
+void budget::predict_module::handle(std::vector<std::string>& args) const {
     if(no_accounts()){
         throw budget_exception("No accounts defined, you should start by defining some of them");
     }