def build_query(args_names, args_values) :
    """
    Transform a list of names and values in a HTTP query string.
    
    Args:
        args_names (:obj:`list` of :obj:`str`): List of names.
        args_values (:obj:`list`): List of values, must have same length of args_names.
    Returns:
        :obj:`str` : Query string.
    """
    ret_str = ''
    first = True
    for (name, value) in zip(args_names, args_values) :
        if value :
            if first :
                ret_str += '?'
                first = False
            else :
                ret_str += '&'
            ret_str += f'{name}={value}'
    return ret_str