Create a function named `divisors`/`Divisors` that takes an integer `n > 1` and returns an array with all of the integer's divisors(except for 1 and the number itself), from smallest to largest. If the number is prime return the string '(integer) is prime' (`null` in C#) (use `Either String a` in Haskell and `Result, String>` in Rust).
#### Example:
```python
divisors(12); #should return [2,3,4,6]
divisors(25); #should return [5]
divisors(13); #should return "13 is prime"
```
from numpy import arange

def divisors(integer):
    # generate array of integers from 2 to integer/2 (rounded down)
    potential_divisors = arange(2, integer//2 + 1)
    # use boolean indexing to extract divisors
    divisors = potential_divisors[integer % potential_divisors == 0]
    # check divisors exist and if not return prime message
    if len(divisors):
        return list(divisors)
    else:
        return '{integer} is prime'.format(integer=integer)
from numpy import arange

def divisors(integer):
    # generate array of integers from 2 to integer/2 (rounded down)
    potential_divisors = arange(2, integer//2 + 1)
    # use boolean indexing to extract divisors
    divisors = potential_divisors[integer % potential_divisors == 0]
    # check divisors exist and if not return prime message
    if len(divisors):
        return list(divisors)
    else:
        return '{integer} is prime'.format(integer=integer)