code: def run_rnaseq_variant_calling(data):
      
      variantcaller = dd.get_variantcaller(data)
      if isinstance(variantcaller, list) and len(variantcaller) > 1:
          logger.error("Only one variantcaller can be run for RNA-seq at "
                       "this time. Post an issue here "
                       "(https://github.com/bcbio/bcbio-nextgen/issues) "
                       "if this is something you need to do.")
          sys.exit(1)
  
      if variantcaller:
          if "gatk-haplotype" in variantcaller:
              data = variation.rnaseq_gatk_variant_calling(data)
          if vardict.get_vardict_command(data):
              data = variation.rnaseq_vardict_variant_calling(data)
          vrn_file = dd.get_vrn_file(data)
      return [[data]]
docs: run RNA-seq variant calling, variation file is stored in `vrn_file`
      in the datadict