Fixed typo with list_mute_ids.
Fixed typo with list_mute_ids.

ryanmcgrath/twython,vivek8943/twython,Hasimir/twython,Fueled/twython,Devyani-Divs/twython,Oire/twython,fibears/twython,akarambir/twython,joebos/twython,ping/twython