What happens when we try to create duplicate share records

Example code :

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Id accountId ;

Id userId;



List<AccountShare> accountShareList = new List<AccountShare>();



// Creating a share record with edit access

AccountShare accShare = new AccountShare();

accShare.AccountId = accountId;

accShare.UserOrGroupId = userId;

accShare.AccessLevel = 'Edit';

accountShareList.add(accShare);



// Creating a share record with read access

accShare = new AccountShare();

accShare.AccountId = accountId;

accShare.UserOrGroupId = userId;

accShare.AccessLevel = 'Edit';

accountShareList.add(accShare);



insert accountShareList;



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1. Now the user will have which access Edit or Read

2. Can we insert two share records with same userorgroupid , accountid and accesslevel but different row cause?

3. Can we insert two share records with same userorgroupid and accountid but different accessleveland different row cause?