def _build_params(dic):
    """
    build params {...}
    :param dic: dict
    :return:  str
    """
    s = ''
    if not dic:
        return s
    if not isinstance(dic, dict):
        raise AssertionError('params must be dict type.')
    for k, v in dic.items():
        if s:
            s += ', {}="{}"'.format(k, v)
        else:
            s = '{}="{}"'.format(k, v)
    return '{%s}' % s
