Need help please

I wanted to change the battlecry() function slightly and add my own tiny upgrades.

My aim was to input something like: 'i can do this' and upon calling the battlecry() function, receiving something like this: 'I CAN DO THIIISSSS!!!!'

I managed to achieve this using two different solutions.

Solution 1:

 def battlecry(self):
     sound = list(self.sound)
     del sound[-2:]
     return ''.join(sound).upper() + (self.sound[-2] + self.sound[-2] + self.sound[-1] + self.sound[-1] + self.sound[-1] + self.sound[-1]).upper() + "!!!!"

Solution 2:

def battlecry(self):
    sound = list(self.sound)
    sound[-2:] = sound[-2] + (sound[-2] + sound[-2] + sound[-1] + sound[-1] + sound[-1] + sound[-1]) + "!!!!"
    return ''.join(sound).upper()

My questions is; Which one of these solutions is more efficient and to broadly put it, 'better'? can you think of any other way to achieve this?

And also I am constantly repeating some of the code such as the sound[-2] and sound[-1] indexes. Is there anyway to shorten this?

I would appreciate any help.

kind regards,

Fahad