code: def _variant_hla(checkpoints):
      
      if not checkpoints.get("hla"):
          return [], []
      hla = [s("hla_to_rec", "multi-batch",
               [["hla", "fastq"],
                ["config", "algorithm", "hlacaller"]],
                 [cwlout("hla_rec", "record")],
                 "bcbio-vc", cores=1, no_files=True),
             s("call_hla", "multi-parallel",
               [["hla_rec"]],
               [cwlout(["hla", "hlacaller"], ["string", "null"]),
                cwlout(["hla", "call_file"], ["File", "null"])],
               "bcbio-vc", ["optitype;env=python2", "razers3=3.5.0", "coincbc"])]
      return hla, [["hla", "call_file"]]
docs: Add hla analysis to workflow, if configured.