def ssh_known_hosts_lines(application_name, user=None):
    """Return contents of known_hosts file for given application.

    :param application_name: Name of application eg nova-compute-something
    :type application_name: str
    :param user: The user that the ssh asserts are for.
    :type user: str
    """
    known_hosts_list = []
    with open(known_hosts(application_name, user)) as hosts:
        for hosts_line in hosts:
            if hosts_line.rstrip():
                known_hosts_list.append(hosts_line.rstrip())
    return(known_hosts_list)
Return contents of known_hosts file for given application.

    :param application_name: Name of application eg nova-compute-something
    :type application_name: str
    :param user: The user that the ssh asserts are for.
    :type user: str