+class DCPError : public StringError
+{
+public:
+ DCPError (std::string s)
+ : StringError (s)
+ {}
+};
+
+class InvalidSignerError : public StringError
+{
+public:
+ InvalidSignerError ();
+};
+
+class ProgrammingError : public StringError
+{
+public:
+ ProgrammingError (std::string file, int line);
+};
+