python: converting string to datetime format

### "15:30" to HH:MM format

```python3
# Check if within an hour
        def calcdiff(start, end):
            time_diff = datetime.datetime.strptime(end, '%H:%M') - datetime.datetime.strptime(start, '%H:%M')
            minutes = int(time_diff.total_seconds()/60)
            return minutes <= 60
```