def get_prefix_from_proxy_group(proxy_group):
    """
    Return prefix by analyzing proxy_group name

    Args:
        proxy_group (str): proxy group name

    Returns:
        str: prefix if exists, empty string if not
    """
    split_name = proxy_group.split('@')[0].split('-')
    if len(split_name) <= 2:
        return ''
    return proxy_group.split('@')[0].split('-')[-3].strip()
