import re


def GetTimeServers(File):
    """ Extract the timeservers from ntp.conf

    Args:
        File - Module to access ntp config file

    Returns:
        ntp_servers - List of configured servers as indicated by ntp.conf
    """
    ntp_conf = File("/etc/ntp.conf")

    # Remove any configuration options that come after the server/pool name
    all_ntp_servers = map(lambda x: re.sub(" .*", "", x),
                          re.findall("\n(?:server|pool)\s*(.*)",
                                     ntp_conf.content_string))

    # Filter fallback NTP server from configuration file.
    user_ntp_servers = filter(lambda x: x != 'ntp.ubuntu.com', all_ntp_servers)
    return user_ntp_servers