import types

def default_handler(obj):
    """JSON handler for default query formatting"""
    if hasattr(obj, 'isoformat'):
        return obj.isoformat()
    if hasattr(obj, 'dump'):
        return obj.dump()
    if isinstance(obj, (set, frozenset, types.GeneratorType)):
        return list(obj)
    if isinstance(obj, BaseException):
        return str(obj)
    raise TypeError("Object of type %s with value of %r "
                    "is not JSON serializable" % (type(obj), obj))