split timestamp by hour
===

I have a list of timestamps in ISO format

`[u"2000-01-01T00:00:00+00:00",  u"2000-01-01T00:00:00+00:00",  ...  ]`

I'm trying to split each string by the hour. However, using `"string".strp(":")` obviously won't work, because of a `too many values to unpack` error (due to several :'s) and `"string".strp(":%S")` gives a value error of `more than one value to unpack`. 
Any ideas?