code: def ssh_known_hosts_lines(application_name, user=None):
      
      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)
docs: 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