code: public Set<Account> getAccountByType(AccountType accountType) {
          Set<Account> accountSet = new HashSet<>();
          for (Account account : accountMap.values()) {
              if (account.getAccountType().equals(accountType)) {
                  accountSet.add(account);
              }
          }
          return accountSet;
      }
docs: 根据账号类型筛选
  
  @param accountType 账户类型
  @return 返回筛选后的账户列表