Multidimensional List Into Single Dimensional List

Create a function that takes a multi-dimensional list and converts it (recursively) into a single-dimensional list and returns it. Use a RECURSIVE approach.

Examples

flatten([[17.2, 5, "code"]]) ➞ [17.2, 5, "code"]

flatten([[[[[2, 14, "rubber"]]], 2, 3, 4]])) ➞ [2, 14, "rubber", 2, 3, 4]

flatten([["dimension"]]) ➞ ["dimension"]

Notes

• Input contains at least one element.
• The use of built-in methods is discouraged.
• A similar version of this challenge can be found here.