85-phone-to-account

public Map<String, Account> phoneToAccount(List<Account> accounts) {
    Map<String,Account> resultMap = new Map<String,Account>();
    for (Account a : accounts)
    {
        if(!String.isBlank(a.Phone))
        {
            resultMap.put(a.Phone, a);
        }
    }
    return resultMap;
}