### Bubble Sort Exercise

Modify [bubble_sort function](https://github.com/codebasics/data-structures-algorithms-python/blob/master/algorithms/2_BubbleSort/bubble_sort.py) such that it can sort following list of transactions happening in an electronic store,
```
elements = [
        { 'name': 'mona',   'transaction_amount': 1000, 'device': 'iphone-10'},
        { 'name': 'dhaval', 'transaction_amount': 400,  'device': 'google pixel'},
        { 'name': 'kathy',  'transaction_amount': 200,  'device': 'vivo'},
        { 'name': 'aamir',  'transaction_amount': 800,  'device': 'iphone-8'},
    ]
``` 
bubble_sort function should take key from a transaction record and sort the list as per that key. For example,
```
bubble_sort(elements, key='transaction_amount')
```
This will sort elements by transaction_amount and your sorted list will look like,
```
elements = [
        { 'name': 'kathy',  'transaction_amount': 200,  'device': 'vivo'},
        { 'name': 'dhaval', 'transaction_amount': 400,  'device': 'google pixel'},
        { 'name': 'aamir',  'transaction_amount': 800,  'device': 'iphone-8'},
        { 'name': 'mona',   'transaction_amount': 1000, 'device': 'iphone-10'},
    ]
``` 
But if you call it like this,
```
bubble_sort(elements, key='name')
```
output will be,
```
elements = [
        { 'name': 'aamir',  'transaction_amount': 800,  'device': 'iphone-8'},
        { 'name': 'dhaval', 'transaction_amount': 400,  'device': 'google pixel'},
        { 'name': 'kathy',  'transaction_amount': 200,  'device': 'vivo'},
        { 'name': 'mona',   'transaction_amount': 1000, 'device': 'iphone-10'},
    ]
``` 

[Solution](https://github.com/codebasics/data-structures-algorithms-python/blob/master/algorithms/2_BubbleSort/bubble_sort_exercise_solution.py)