gistfile1.py

# only show the fields specified in the json properties list of the model
if hasattr(item, 'json_properties'):
    json_properties = getattr(item, 'json_properties')

    properties = {}
    for k,v in item.__dict__.iteritems():
        if k in json_properties:
            properties[k] = v
# the json properties list is not available, so copy all the properites
else:
    properties = item.__dict__.copy()