reference:
  class: File
  location: keep:a3af04432df3d71d22f2fe8be549ba96+5974/hg38.fa
sample: ERR1726424
gvcflist:
  class: File
  location: /data-sdd/pgp/arvados-tutorial/src/variantcalling/sample-files.list
gvcf1:
  class: File
  location: keep:dec5da8ebcda12b3eece8705a4391f55+2510/ERR1726424.gatk.g.vcf.gz

gvcf2:
  class: File
  location: keep:dec5da8ebcda12b3eece8705a4391f55+2510/ERR1726424.gatk.g.vcf_10.gz