code: def use_vqsr(algs, call_file=None):
      
      from bcbio.variation import vcfutils
      vqsr_callers = set(["gatk", "gatk-haplotype"])
      vqsr_sample_thresh = 50
      vqsr_supported = collections.defaultdict(int)
      coverage_intervals = set([])
      for alg in algs:
          callers = alg.get("variantcaller")
          if isinstance(callers, six.string_types):
              callers = [callers]
          if not callers:  # no variant calling, no VQSR
              continue
          if "vqsr" in (alg.get("tools_off") or []):  # VQSR turned off
              continue
          for c in callers:
              if c in vqsr_callers:
                  if "vqsr" in (alg.get("tools_on") or []):  # VQSR turned on:
                      vqsr_supported[c] += 1
                      coverage_intervals.add("genome")
                  # Do not try VQSR for gVCF inputs
                  elif call_file and vcfutils.is_gvcf_file(call_file):
                      pass
                  else:
                      coverage_intervals.add(alg.get("coverage_interval", "exome").lower())
                      vqsr_supported[c] += 1
      if len(vqsr_supported) > 0:
          num_samples = max(vqsr_supported.values())
          if "genome" in coverage_intervals or num_samples >= vqsr_sample_thresh:
              return True
      return False
docs: Processing uses GATK's Variant Quality Score Recalibration.