docs: def update_case(case_obj, existing_case):
      """Update an existing case
      
      This will add paths to VCF files, individuals etc
      
      Args:
          case_obj(models.Case)
          existing_case(models.Case)
      
      Returns:
          updated_case(models.Case): Updated existing case
      """
      variant_nrs = ['nr_variants', 'nr_sv_variants']
      individuals = [('individuals','_inds'), ('sv_individuals','_sv_inds')]
      
      updated_case = deepcopy(existing_case)
      
      for i,file_name in enumerate(['vcf_path','vcf_sv_path']):
          variant_type = 'snv'
          if file_name == 'vcf_sv_path':
              variant_type = 'sv'
          if case_obj.get(file_name):
              if updated_case.get(file_name):
                  LOG.warning("VCF of type %s already exists in case", variant_type)
                  raise CaseError("Can not replace VCF in existing case")
              else:
                  updated_case[file_name] = case_obj[file_name]
                  updated_case[variant_nrs[i]] = case_obj[variant_nrs[i]]
                  updated_case[individuals[i][0]] = case_obj[individuals[i][0]]
                  updated_case[individuals[i][1]] = case_obj[individuals[i][1]]
  
      return updated_case