import simplejson
[...]
json_response = xbmc.executeJSONRPC('{"jsonrpc": "2.0", "method": "VideoLibrary.GetEpisodes", "params": { "properties": ["playcount", "resume", "plot", "season", "episode", "showtitle", "thumbnail", "fanart", "file", "lastplayed"], "sort": { "method": "episode" }, "tvshowid":%s }, "id": 1}' % tvshow)
jsonobject = simplejson.loads(json_response)
if jsonobject['result'].has_key('items'):
for item in jsonobject['result']['items']:
if item.has_key('resume') and item['resume']['position'] > 0:
#mark this item as partially watched
item['partiallywatched'] = True
playcount = item['playcount']
#whatever goes here