Hi guys!

I'm a unittest newbie, so it's possible there's a better solution than what I'm proposing here. If there is, please let me know. 

I recently submitted this PR, and I had to use assertSequenceEqual twice, just because I wanted to compare 3 sequences to each other rather than 2.

Wouldn't it be possible to make assertEqual and its entire family (including assertSequenceEqual and the dozen of other methods) accept an arbitrary number of arguments, and compare all of them to each other? That way I could do this: 

    self.assertSequenceEqual(sliced_tuple_0, sliced_tuple_1, sliced_range)

We could discuss whether they'll do the faster version of a == b == c, or a more extensive check between every 2 items individually.

What do you think?