summing only the numbers contained in a list

Question

Give a method that sums all the numbers in a list. The method should be able to skip elements that are not numbers. So, sum([1, 2, 3]) should be

Answer 1

def foo(list):
dict= "ABCDEFGHIJKLMN"
n=0
for i in range(0,len(list)-1):
    if str(list[i]) in dict:
        ""
    else:    
        n= n+list[i]
return n
print foo([1,2,3,4,5,6,"A","B"])