Best to run a python shell and test it, such as:
>>> "x".join (["a", "b", "c"])
'axbxc'
>>> "abc".join (["M"])
'M'
The "x" was used as the thing in between the values in the iterable. Next time "abc" was used in between, except there was only one value, so there was no in between needed.
Then refer to the docs as per CoryKramer comment.
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