Exercise: Swap Two Variables¶

Write a program swap.py that exchanges (swaps) two variables var1 and var2, both str type.

To output the values before and after the swap operation, use the print() function.
```
var1 = 1
var2 = 2

print('Before:', var1, var2)
# let the miracle happen: exchange the two variables!
print('After:', var1, var2)
```
Once the miracle took place, the output of the program should look like follows:
```
$ python swap.py
Before: 1 2
After: 2 1
```