diff --git a/src/CParser.hpp b/src/CParser.hpp
index 96d4979..6db95e1 100644
--- a/src/CParser.hpp
+++ b/src/CParser.hpp
@@ -20,12 +20,19 @@
 using x3::lexeme;
 using ascii::space;
 
+class InvalidCommandException : public std::invalid_argument {
+public:
+    using std::invalid_argument::invalid_argument;
+    ~InvalidCommandException() override;
+};
+
 class TooManyArgumentsException : public std::invalid_argument {
 public:
     using std::invalid_argument::invalid_argument;
     ~TooManyArgumentsException() override;
 };
 
+
 class CParser {
 public:
     CParser(const CTree& tree);