code: def _get_tgt_length(self, var):
          
          if var.type == "g" or var.type == "m":
              return float("inf")
          else:
              # Get genomic sequence access number for this transcript
              identity_info = self.hdp.get_tx_identity_info(var.ac)
              if not identity_info:
                  raise HGVSDataNotAvailableError(
                      "No identity info available for {ac}".format(ac=var.ac))
              tgt_len = sum(identity_info["lengths"])
              return tgt_len
docs: Get the total length of the whole reference sequence