Challenge 16 - Grouping Data into CSV Files - Solution

Challenge 16 - Grouping Data into CSV Files - Solution
You were asked to split a single sales CSV file into smaller ones based on groups, named according to the group names. As an example, if the original file had the following data:

Sales Group
100 b
200 a
300 a

You would generate two files: one named Group_a, and one named Group_b. They would have the following structure:

Sales Group
200 a
300 a

and

Sales Group
100 b

Your solution to this task should be generic — that is, it should work for any number of groups, and the names of the groups should not matter.