Write a function, uncompress, that takes in a string as an argument. The input string will be formatted into multiple groups according to the following pattern:

    `<number><char>`

    `for example, '2c' or '3a'.`

The function should return an uncompressed version of the string where each 'char' of a group is repeated 'number' times consecutively. You may assume that the input string is well-formed according to the previously mentioned pattern.

uncompress("2c3a1t")

uncompress("4s2b")

uncompress("2p1o5p")

uncompress("3n12e2z")

uncompress("127y")