How to Replace a sublist with another sublist in python

Say, i have a list of elements, 

ele = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

After performing some operations, i need to revise the list by replacing some elements (sublist) of the mail list, with some derived elements (another sublist).

Say, i need to replace the sublist [2, 3, 4] with [90, 91]

This is one of the critical operation in my program to process further steps and hence i am seeking some concurrent method to achieve this.

Please guide.