def METHOD_NAME(location=None):
    """
    Generate a single CA file with all the PEMs
    :param str location: we can specify a specific CS location
                         where it's written a directory where to find the CAs and CRLs
    :return: directory where the file crls.pem which contains all CRLs is created
    """
    caDir = Locations.getCAsLocation()
    if not caDir:
        return S_ERROR("No CAs dir found")
    # look in what's normally /etc/grid-security/certificates
    if os.path.isfile(os.path.join(os.path.dirname(caDir), "crls.pem")):
        return S_OK(os.path.join(os.path.dirname(caDir), "crls.pem"))
    # look in what's normally /opt/dirac/etc/grid-security
    diracCADirPEM = os.path.join(os.path.dirname(Locations.getHostCertificateAndKeyLocation(location)[0]), "crls.pem")
    if os.path.isfile(diracCADirPEM):
        return S_OK(diracCADirPEM)
    # Now we create it in tmpdir
    fn = tempfile.mkstemp(prefix="crls", suffix=".pem")[1]
    try:
        with open(fn, "w") as fd:
            for caFile in os.listdir(caDir):
                caFile = os.path.join(caDir, caFile)
                result = X509CRL.X509CRL.instanceFromFile(caFile)
                if not result["OK"]:
                    continue
                chain = result["Value"]
                fd.write(chain.dumpAllToString()["Value"])
            return S_OK(fn)
    except OSError as err:
        gLogger.warn(err)
    return S_ERROR("Could not find/generate CRLs")