AM_DeletePreviousKey py2.7

#Delete the previous key from your selection (work only on your timeline)

import maya.cmds as mc

sel = mc.ls(sl=True, flatten=True)
ctime = mc.currentTime(query=True)
playback = mc.playbackOptions(animationStartTime=True, query=True), mc.playbackOptions(animationEndTime=True, query=True)
previouskey = mc.findKeyframe(which='previous')

for obj in sel:
    if previouskey >= playback[0] and previouskey < playback[1]:
        mc.cutKey(cl=True,time=(previouskey, previouskey))