join()

[franzferdinand]

I'm doing this "Write code that removes whitespace at the beginning
and end of a string, and normalizes whitespace between words to be a
single space character"

I can do it using split()

>>> raw = "      the     weather is     sunny                  today       "
>>> raw.split()
['the', 'weather', 'is', 'sunny', 'today']

But how do I do it using join() ?? Thanks