Wrong error message for edit command

[RunjiaChen]

Description

The edit command does not give the same error message for different values

Steps to reproduce

1. Launch the application for the first time to load initial data.
2. Run the edit command for a very large number

Expected behaviour

It should result in an invalid index error message

Actual behaviour

Now, it says invalid command format

Reason for severity

Doesnt really affect the functionality of the application

Ideas

May be caused as you did not check for whether the number counts as an integer or it causes overflow