How to pick a random number every time from a list

The goal: pick a random number from a list every time a chunk is generated

Python code example to make it more clear.

I have this list:

listbytes = [87, 88, 89, 90]

And this function which splits the data:

def chunks(lst, n):
"Yield successive chunks from lst, where n is a list of possible sizes"
    i = 0
    while i < len(lst):
        k = min(random.choice(n), len(lst) - i)
        yield lst[i:i + k]
        i += k

And I call it this way:

for chunk in chunks(d, listbytes):
    ......

Every chunk has a random size between the ints in the listbytes variable, so: 1 chunk may have the size of 87, the next one may have the size of 90, and so on..

Go code:

func split(buf []byte, lim int) [][]byte {
    var chunk []byte
    chunks := make([][]byte, 0, len(buf)/lim+1)
    for len(buf) >= lim {
        chunk, buf = buf[:lim], buf[lim:]
        chunks = append(chunks, chunk)
    }
    if len(buf) > 0 {
        chunks = append(chunks, buf[:len(buf)])
    }
    return chunks
}

And I call it this way:

for _, chunk := range split(buf[:n], 100) {
    .......

How can I achieve the same goal but in go?