The current_wallet inclusion adds nothing to the task.

For a transaction record that doesn't exist, it can be represented by its absence, an empty list, a list with a None, or a None i.e:

Half the task is dealing with the terrible input format... Why?

Does not use new test framework

• No sample tests
• No random tests
• The requirement to add current_wallet to the result adds nothing to the task
• Duplicate of all the other map/filter/reduce katas