## The challenge

We want an array, but not just any old array, an array with contents!

Write a function that produces an array with the numbers `` to `N-1` in it.

For example, the following code will result in an array containing the numbers `` to `4`:

 ``````1 `````` ``````arr(5) # => [0,1,2,3,4] ``````

Note: The parameter is optional. So you have to give it a default value.

## The solution in Python code

Option 1:

 ``````1 2 `````` ``````def arr(n=0): return [x for x in range(n) if n>0] ``````

Option 2:

 ``````1 2 `````` ``````def arr(n=0): return list(range(n)) ``````

Option 3:

 ``````1 2 3 4 5 `````` ``````def arr(n=0): aux = [] for x in range(n): aux.append(x) return aux ``````

## Test cases to validate our solution

 `````` 1 2 3 4 5 6 7 8 9 10 `````` ``````import test from solution import arr @test.it("Basic Tests") def basic_tests(): @test.it('Basic Test Cases') def basic_test_cases(): test.assert_equals(arr(4), [0,1,2,3]) test.assert_equals(arr(0), []) test.assert_equals(arr(), []) ``````