code: func opcodeCheckSigVerify(op *parsedOpcode, vm *Engine) error {
  	err := opcodeCheckSig(op, vm)
  	if err == nil {
  		err = abstractVerify(op, vm, ErrCheckSigVerify)
  	}
  	return err
  }
docs: // opcodeCheckSigVerify is a combination of opcodeCheckSig and opcodeVerify.
  // The opcodeCheckSig function is invoked followed by opcodeVerify.  See the
  // documentation for each of those opcodes for more details.
  //
  // Stack transformation: signature pubkey] -> [... bool] -> [...]