Is there a shorter way to make this function?

Question

B. front_x Given a list of strings, return a list with the strings in sorted order, except group all the strings that begin with \'x\' first. e.g. [\'mix\', \'xyz\', \'apple\',

Answer 1

The error is because .sort() is in-place. It returns None, and you can't do None + None

Since Python's sort is stable, you can also accomplish this by doing two sorts

>>> L = ['mix', 'xyz', 'apple', 'xanadu', 'aardvark']
>>> sorted(sorted(L), key=lambda x:x[0]!='x')
['xanadu', 'xyz', 'aardvark', 'apple', 'mix']

And the in-place version

>>> L.sort()
>>> L.sort(key=lambda x:x[0]!='x')
>>> L
['xanadu', 'xyz', 'aardvark', 'apple', 'mix']