make static based methods static

app/forms.py

@@ -28,12 +28,14 @@ class RegistrationForm(FlaskForm):
     )
     submit = SubmitField("Register")
 
-    def validate_username(self, username):
+    @staticmethod
+    def validate_username(username):
         user = User.query.filter_by(username=username.data).first()
         if user is not None:
             raise ValidationError("That username is not available.")
 
-    def validate_email(self, email):
+    @staticmethod
+    def validate_email(email):
         user = User.query.filter_by(email=email.data).first()
         if user is not None:
             raise ValidationError("That email address is not available.")