[optimizations] Make some minor optimizations to help with long collections

[juharris]

I came across this library and decided to make some very minor optimizations.

• Avoid identity lambda which can slow down things a little bit: https://stackoverflow.com/a/22291628/1226799
• Avoid calling the accessor function twice.
• Use a tuple instead of list for regex.finditer
• Sort suggestions in-place instead of making a new list.
• Use map + operator.itemgetter(-1) instead of a generator + z[-1]

There are probably more optimizations we can do like not making tuples in suggestions as big. But that would involve a bigger refactoring.

[amjith]

Very nice.