def is_any(type_strings, struct):
    """
    Return true if all types are valid, and there are no type constraints.
    """
    ALL_PROPERTY_NAMES = {'exclusiveMaximum', 'format', 'minItems',
        'pattern', 'required', 'multipleOf', 'maximum', 'minimum',
        'maxItems', 'minLength', 'uniqueItems', 'additionalItems',
        'maxLength', 'items', 'exclusiveMinimum', 'properties',
        'additionalProperties', 'minProperties', 'maxProperties',
        'patternProperties'}
    return len(type_strings) == 6 and not set(struct.keys()
        ) & ALL_PROPERTY_NAMES
