code: def get_aligner_with_aliases(aligner, data):
      
      aligner_aliases = {"sentieon-bwa": "bwa"}
      from bcbio import structural
      if not aligner and "gridss" in structural.get_svcallers(data):
          aligner = "bwa"
      return aligner_aliases.get(aligner) or aligner
docs: Retrieve aligner index retriever, including aliases for shared.
  
      Handles tricky cases like gridss where we need bwa indices even with
      no aligner specified since they're used internally within GRIDSS.