Insert Account with related Contact and Opportunity in Lightning Component

public class InsertAccWithConOpp{
    @AuraEnabled
    public static String createparentchildrecord(Account acc, Contact con, Opportunity opp){
        String resultVal ='';
        SavePoint sp = Database.setSavePoint();
        try{
            insert acc;
            con.AccountID  = acc.id;
            insert con;
            opp.AccountID  = acc.id;
            insert opp;
            resultVal=''+acc.ID;
        }
        catch(Exception e){
            Database.rollback(sp);
        }
        return resultVal;
    }
}

<aura:component controller='InsertAccWithConOpp' implements="force:appHostable,flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId,forceCommunity:availableForAllPageTypes,force:lightningQuickAction" access="global">
    <aura:attribute name='acc' type='Account' default="{SobjectType :'Account'}"/>
    <aura:attribute name='con' type='Contact' default="{SobjectType :'Contact'}"/>
    <aura:attribute name='opp' type='Opportunity' default="{SobjectType :'Opportunity'}"/>
    <aura:attribute name='myVal' type='String'/>
    <aura:attribute name='resultVal' type='String'/>
    
    <div class="outerbox">    
        <lightning:card title='sObject Form'>
            <div class="innerbox">
                <lightning:tabset  selectedTabId='{!v.myVal}'>
                    <lightning:tab label='Account' id='accId'>
                        <lightning:input label='AccountName' value='{!v.acc.Name}'/>
                        <lightning:input label='Phone' value='{!v.acc.Phone}'/>
                        <lightning:input label='AnnualRevenue' value='{!v.acc.AnnualRevenue}'/>
                        <lightning:button label='Next' onclick="{!c.nextFunction}"/>
                    </lightning:tab>
                    <lightning:tab label='contact' id='conId'>
                        <lightning:input label='FirstName' value='{!v.con.FirstName}'/>
                        <lightning:input label='LastName' value='{!v.con.LastName}'/>
                        <lightning:button label='Previous' onclick='{!c.prevFunction}'/>
                        <lightning:button label='Next' onclick='{!c.nextFunction}'/>
                    </lightning:tab>
                    <lightning:tab label='opportunity' id='oppId'>
                        <lightning:input label='opportunity Name' value='{!v.opp.Name}'/>
                        <lightning:input label='Stage' value='{!v.opp.StageName}'/>
                        <lightning:input label='Close Date' value='{!v.opp.CloseDate}' type='Date'/>
                        <lightning:button label='Previous' onclick='{!c.prevFunction}'/>
                        <lightning:button label='submit' onclick='{!c.submitFunction}'/>
                    </lightning:tab>
                </lightning:tabset>
            </div>
        </lightning:card>
    </div>
    
</aura:component>

({
    nextFunction : function(component, event, helper) {
        var val = component.get('v.myVal');
        if(val == 'accId'){
            component.set('v.myVal','conId');
        }
        else if(val == 'conId'){
            component.set('v.myVal','oppId');
        }
    },
    prevFunction : function(component, event, helper) {
        var val = component.get('v.myVal');
        if(val=='conId'){
            component.set('v.myVal','accId');
        }
        else if(val=='oppId'){
            component.set('v.myVal','conId');
        }
    },
    submitFunction : function(component, event, helper) {
        var accs =component.get('v.acc');
        var cons =component.get('v.con');
        var opps =component.get('v.opp');
        var action = component.get('c.createparentchildrecord');
        action.setParams({'acc':accs, 'con':cons, 'opp':opps});
        action.setCallback(this, function(response){
            var state = response.getState();
            if(state === 'success'){
                var r = response.getReturnValue();
                component.set('v.resultVal',r);
            }else{
                //console.log('failed');
                component.set('v.resultVal','failed');
            }
        });
        $A.enqueueAction(action);
    }
})

.THIS.innerbox{
    width:350px;
    height:400px;
    padding:20px;
    margin-left:20px;
    border:2px solid blue;
}
.THIS.outerbox{
    width:450px;
    height:370px;
    padding:20px;
    border:2px solid blue;
    margin-left:450px;
    margin-top:20px;
}

<aura:application extends="force:slds">
    <c:InsertAccountContactOpportunity/>
</aura:application>