Error storing values longer than 500 characters

[ajdevries]

There is a problem with running Spartify on the app engine, and storing values of the playlist that are longer than 500 characters. Getting the following error:

ERROR 2013-08-19 18:03:29,125 util.py:51] JSON service call pop(**{'party_id': u'Z0ZNJ'}) failed:
Traceback (most recent call last):
File "/Users/aj/deralradio/spartify/util.py", line 48, in get
out['response'] = attr(**args) if callable(attr) else attr
File "/Users/aj/deralradio/spartify/handlers.py", line 7, in wrap
return f(self, party_id.upper(), _args, *_kwargs)
File "/Users/aj/deralradio/spartify/handlers.py", line 43, in pop
party.Party(party_id).pop_track()
File "/Users/aj/deralradio/spartify/party.py", line 19, in pop_track
self._queue.add(t.to_dict(), 0)
File "/Users/aj/deralradio/spartify/playback.py", line 33, in add
self._save()
File "/Users/aj/deralradio/spartify/playback.py", line 26, in _save
stores.queues[self._party_id] = data
File "/Users/aj/deralradio/spartify/stores.py", line 81, in setitem
self.timeout_store(key, value)
File "/Users/aj/deralradio/spartify/stores.py", line 89, in timeout_store
StoreNode.set(key, value, self._collection)
File "/Users/aj/deralradio/spartify/stores.py", line 44, in set
model = cls(key_name=key, value=value, collection=collection)
File "/Users/aj/Desktop/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/db/init.py", line 970, in init
prop.set(self, value)
File "/Users/aj/Desktop/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/db/init.py", line 614, in set
value = self.validate(value)
File "/Users/aj/Desktop/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/db/init.py", line 2851, in validate
% (self.name, len(value), self.MAX_LENGTH))
BadValueError: Property value is 574 characters long; it must be 500 or less.