Model: Add missing custom execption file.

src/Model/Except.py

+# -*- coding: utf-8 -*-
+
+from PyQt5.QtWidgets import (
+    QApplication, QMessageBox,
+)
+
+####################################
+# Message Box for python exception #
+####################################
+
+def exception_message_box(exception):
+    msg = QMessageBox()
+    msg.setIcon(QMessageBox.Critical)
+
+    msg.setText("Exception :")
+    msg.setInformativeText(f"{exception}")
+    msg.setWindowTitle("Exception")
+
+    msg.exec_()
+
+################
+# Custom error #
+################
+
+class ExeceptionWithMessageBox(Exception):
+    def __init__(self, title = "Exeception"):
+        self.title = title
+
+    def header(self):
+        return "Generic error message"
+
+    def short_message(self):
+        return "Undefined error message"
+
+    def message(self):
+        return "Undefined error message"
+
+    def alert(self):
+        msg = QMessageBox()
+        msg.setIcon(QMessageBox.Critical)
+
+        msg.setText(f"{self.header()} : {self.short_message()}")
+        msg.setInformativeText(f"{self.message()}")
+        msg.setWindowTitle(f"{self.title}")
+
+        msg.exec_()
+
+
+class FileFormatError(ExeceptionWithMessageBox):
+    def __init__(self, filename, reason):
+        super(FileFormatError, self).__init__(title = "FileFormatError")
+
+        self.reason = reason
+        self.filename = filename
+
+    def __str__(self):
+        return f"Invalid file format: '{self.filename}'\n{self.message()}"
+
+    def header(self):
+        return "File format error"
+
+    def short_message(self):
+        return "Invalid file format"
+
+    def message(self):
+        return f"Invalid file '{self.filename}' format because of '{self.reason}'"