This kata is part of the collection [Mary's Puzzle Books](https://www.codewars.com/collections/marys-puzzle-books).
Mary brought home a "spot the differences" book. The book is full of a bunch of problems, and each problem consists of two strings that are similar. However, in each string there are a few characters that are different. An example puzzle from her book is:
```
String 1: "abcdefg"
String 2: "abcqetg"
```
Notice how the "d" from String 1 has become a "q" in String 2, and "f" from String 1 has become a "t" in String 2.
It's your job to help Mary solve the puzzles. Write a program `spot_diff`/`Spot` that will compare the two strings and return a list with the positions where the two strings differ. In the example above, your program should return `[3, 5]` because String 1 is different from String 2 at positions 3 and 5.
NOTES:
```if-not:csharp
• If both strings are the same, return `[]`
```
```if:csharp
• If both strings are the same, return `new List()`
```
• Both strings will always be the same length
• Capitalization and punctuation matter
def spot_diff(s1, s2):
  r=[]
  for i in range (len(s1)):
    if s1[i]!=s2[i]: r.append(i)
  return r
def spot_diff(s1, s2):
  r=[]
  for i in range (len(s1)):
    if s1[i]!=s2[i]: r.append(i)
  return r