code: def _get_calls(data, cnv_only=False):
      
      cnvs_supported = set(["cnvkit", "battenberg"])
      out = {}
      for sv in data.get("sv", []):
          if not cnv_only or sv["variantcaller"] in cnvs_supported:
              out[sv["variantcaller"]] = sv
      return out
docs: Retrieve calls, organized by name, to use for heterogeneity analysis.