def METHOD_NAME(self, df: pd.DataFrame) -> pd.DataFrame:
    """Intelligently strip FQDN from peer hostname if necessary.
    In some cases, the hostname returned by the NOS is without the
    domain name while the hostname advertised in LLDP is the FQDN.
    This means we cannot use LLDP to determine peering interfaces.
    This routine addresses this by intelligently stripping domain
    name from hosts if they're known without FQDN
    Args:
        df: LLDP pandas Dataframe
    Returns:
        pandas Dataframe with the peerHost entry fixed
    """
    hosts = set(df.hostname.unique().tolist())
    peerhosts = set(df.peerHostname.unique().tolist())
    ph_map = {hname: (hname.split('.')[0]
                      if hname.split('.')[0] in hosts else hname)
              for hname in peerhosts}
    df['peerHostname'] = df.peerHostname.apply(lambda x, ph_map:
                                               ph_map[x], args=(ph_map,))
    return df