Evaluate a jsonnet input string.

    contents
        Raw jsonnet string to evaluate.

    jsonnet_library_paths
        List of jsonnet library paths.

def evaluate(contents, jsonnet_library_paths=None):
    '''
    Evaluate a jsonnet input string.

    contents
        Raw jsonnet string to evaluate.

    jsonnet_library_paths
        List of jsonnet library paths.
    '''

    if not jsonnet_library_paths:
        jsonnet_library_paths = __salt__['config.option'](
                'jsonnet.library_paths', ['.'])
    return salt.utils.json.loads(
            _jsonnet.evaluate_snippet(
                "snippet",
                contents,
                import_callback=partial(
                    _import_callback, library_paths=jsonnet_library_paths)))