code: def _mutect_variant_stats(variant, sample_info):
      
  
      # Parse out the AD (or allele depth field), which is an array of [REF_DEPTH, ALT_DEPTH]
      ref_depth, alt_depth = sample_info["AD"]
      depth = int(ref_depth) + int(alt_depth)
      vaf = float(alt_depth) / depth
  
      return VariantStats(depth=depth, alt_depth=alt_depth, variant_allele_frequency=vaf)
docs: Parse a single sample"s variant calling statistics based on Mutect"s (v1) VCF output
  
      Parameters
      ----------
      variant : varcode.Variant
      sample_info : dict
          Dictionary of Mutect-specific variant calling fields
  
      Returns
      -------
      VariantStats