Write a function long_high_word(wordlist) that takes a non-empty list of words wordlist (each of which is a string), and returns the word which is longest, and in the instance of multiple words having that length, is highest among them, based on unicode sort order. for example:
> > > long_high_word(['a', 'cat', 'sat'])
'sat'
> > > long_high_word(['saturation', 'of', 'colour'])
'saturation'
> > > long_high_word(['samiam'])
'samiam'