What hash algorithm does Python's dictionary mapping use?

I was messing around with making a command line parser and was wondering what kind of hash algorithm python dict's use?

The way I have it set up, I have a pattern match algorithm which matches tokenized input sequences with a dictionary key. Some of the keys are relatively long (length 5 or 6 tuples of 6-7 character strings). I was wondering if there was a point at which long dictionary keys significantly reduce the efficiency of key retrieval.