# Create a function that takes a list of numbers and returns a list where each
# number is the sum of itself + all previous numbers in the list.
# Return an empty list if the input is an empty list.


def cumulative_sum(lst):
    total = 0
    sum = []
    for x in lst:
        total = total + x
        sum.append(total)
    return sum



print(cumulative_sum([1, 2, 3])) # [1, 3, 6]
print(cumulative_sum([1, -2, 3])) # [1, -1, 2]
print(cumulative_sum([3, 3, -2, 408, 3, 3])) # [3, 6, 4, 412, 415, 418]
