flat_map function:

Flat map a list into a new list using a function. If the first argument is a list, activate the second argument on each item, and if that returns a list, add all the items to a new list.

Examples:

• running: (flat_map ["a,b,c", "d,e", 4, "g"], (split . ",")) will give: ["a", "b", "c", "d", "e", "g"] Because it will split each element by the comma, and return a list of all those lists.

• running: (flat_map [1, 2, 3, 4], (.len)) will give: []

• running: (flat_map {}, true) will return nothing