# Strange behaviour

I am new to Sage, so please help me understand the following: How come

```
map(lambda x: mod(x,2),[4,3,2,1,1])
```

returns the perfectly sane answer [0,1,0,1,1]

but trying to compute the sum

```
sum(map(lambda x: mod(x,2),[4,3,2,1,1]))
```

gives the value 1, and not 3. Somehow, it seems that sage thinks that I wish to apply the inner lambda again on the result of the sum.