Select Validation in Form

Select list in Form:

<Label text="Group" />
          <Select width="100%" id="group">
            <items>
              <core:Item text="Select" key="1"/>
              <core:Item text="B.Tech" key="2"/>
              <core:Item text="M.C.A" key="3"/>
              <core:Item text="M.Tech" key="4"/>
            </items>
          </Select>
          
            <Label text="Sex" />

var select =  this.getView().byId("group").getSelectedKey();
    
     if(select==1){
        
         sap.m.MessageBox.alert("Please select the course");
         return false;
     }