code: public void transfer(Account from, Account to, int amount) {
          from.withdraw(amount);
          to.diposit(amount);
      }
docs: /* (non-Javadoc)
  @see org.jboss.arquillian.framework.spock.AccountService#transfer(org.jboss.arquillian.framework.spock.Account, org.jboss.arquillian.framework.spock.Account, java.math.BigDecimal)