checker = Validator()
schema = {'type': 'object', 'properties': {'source': {'type': 'object',
    'properties': {'name': {'type': 'string'}}, 'additionalProperties': False}}
    }
data = {'source': {'name': 'blah', 'bad_key':
    'This data is not allowed according to the schema.'}}
checker.validate(data, schema)
python data structure validation using Validator (or something similar)