Hi! Could someone explain why this solution does only return 8000 and does not continue to add other elements but the very first?

def over_nine_thousand(lst):

n=0

Sum = 0

while Sum <= 9000:

Sum += lst[n]

n+=1

return Sum

#Uncomment the line below when your function is done

print(over_nine_thousand([8000, 900, 120, 5000]))