Pep8 blank-line fixes in marathon.py.
Pep8 blank-line fixes in marathon.py.

amitaekbote/dcos,lingmann/dcos,mesosphere-mergebot/dcos,kensipe/dcos,jeid64/dcos,lingmann/dcos,mnaboka/dcos,mellenburg/dcos,kensipe/dcos,vishnu2kmohan/dcos,jeid64/dcos,jeid64/dcos,mnaboka/dcos,asridharan/dcos,BenWhitehead/dcos,GoelDeepak/dcos,vishnu2kmohan/dcos,lingmann/dcos,GoelDeepak/dcos,amitaekbote/dcos,kensipe/dcos,mesosphere-mergebot/dcos,GoelDeepak/dcos,mellenburg/dcos,surdy/dcos,surdy/dcos,mesosphere-mergebot/mergebot-test-dcos,mesosphere-mergebot/dcos,branden/dcos,GoelDeepak/dcos,asridharan/dcos,vishnu2kmohan/dcos,dcos/dcos,dcos/dcos,mnaboka/dcos,branden/dcos,mellenburg/dcos,mnaboka/dcos,mesosphere-mergebot/mergebot-test-dcos,dcos/dcos,mellenburg/dcos,kensipe/dcos,amitaekbote/dcos,BenWhitehead/dcos,darkonie/dcos,asridharan/dcos,darkonie/dcos,dcos/dcos,darkonie/dcos,branden/dcos,mesosphere-mergebot/dcos,mnaboka/dcos,mesosphere-mergebot/mergebot-test-dcos,amitaekbote/dcos,lingmann/dcos,asridharan/dcos,vishnu2kmohan/dcos,darkonie/dcos,dcos/dcos,surdy/dcos,BenWhitehead/dcos,mesosphere-mergebot/mergebot-test-dcos,BenWhitehead/dcos,jeid64/dcos,branden/dcos,surdy/dcos,darkonie/dcos