Upsert List<SObject> with External Id with "AllOrNothing" Error Example

gistfile1.txt

    public static List<Database.UpsertResult> upsertListSObjectsWithExternalIdWithAllOrNothingErrorExample() {
        List<SObject> records = new List<SObject>();
        
        Account a = new Account(
            Name = 'Example Company',
            External_Id__c = 'ExampleCompany'
        );
        
        records.add(a);
        
        Schema.SObjectField f = Account.Fields.External_Id__c;
        
        /* this throws a compilation error of 
         * Compile Error: Upsert requires a concrete SObject type at line ## column ##
         */
        return Database.Upsert(records, f, false);
    }