Write a function cumsum() that takes a list l as argument and returns the cumulative sum (also known as the prefix sum) of l, which is a list, say cs of the same length as l such that each element cs[i] is equal to the sum of the first i + 1 elements of l, i. e.,cs[i] == l[0] + l[1] + l[2] + + l[i]you should not modify the argument list l in any way. also, you do not need to assume that l contains numbers; your function should work with any elements that support +. practice goal: although not required, try to solve this without using a nested loop. in this case, you’ll have to write a loop that runs two accumulations in tandem. the first is the standard sum-so-far that we’ve seen several times. the second is an accumulation of the intermediate sum-so-far values into a list (e. g., via an .append() operation); the final value of this list is the desired result.