Add files after python session and annotations

session_1_errors_and_exceptions/myfunction.py

+class MyExceptionValue(ValueError):
+    def __init__(self, error_code):
+        self.error_code = error_code
+
+    def __str__(self):
+        return f"The error number was {self.error_code}"
+
+    def __repr__(self):
+        return f"<Exception>: The error number was {self.error_code}"
+
+
+def func():
+    raise MyExceptionValue(404)