code: def _infer_transform_options(transform):
      
      TransformOptions = collections.namedtuple("TransformOptions",
                                                ['CB', 'dual_index', 'triple_index', 'MB', 'SB'])
      CB = False
      SB = False
      MB = False
      dual_index = False
      triple_index = False
      for rx in transform.values():
          if not rx:
              continue
          if "CB1" in rx:
              if "CB3" in rx:
                  triple_index = True
              else:
                  dual_index = True
          if "SB" in rx:
              SB = True
          if "CB" in rx:
              CB = True
          if "MB" in rx:
              MB = True
      return TransformOptions(CB=CB, dual_index=dual_index, triple_index=triple_index, MB=MB, SB=SB)
docs: figure out what transform options should be by examining the provided
      regexes for keywords