# Python Interfaces

### HackerRank

The AdvancedArithmetic interface and the method declaration for the abstract divisorSum(n) method are provided for you in the editor below. Complete the implementation of Calculator class, which implements the AdvancedArithmetic interface. The implementation for the divisorSum(n) method must return the sum of all divisors of n.

## Code

#### Since I’ll need all the divisors of n, that’ll be a list.

```
[]
```

#### To grab them I can just do a for loop and add to list if n % i.

```
[i for i in range(1, n+1) if n % i == 0]
```

#### Sum up that list

```
sum([i for i in range(1, n+1) if n % i == 0]
```

## Final Code

```
class AdvancedArithmetic(object):
def divisorSum(n):
raise NotImplementedError
class Calculator(AdvancedArithmetic):
def divisorSum(self, n):
return sum([i for i in range(1, n+1) if n % i == 0])
```

## Conclusion

Always good to keep me on my toes.