How to calculate Available physical of an item given the inventLocationId that shown on the on hand form

How to get available physical for an Item and for Warehouse in AX 2012 / D365 FO 

InventDimParm       invDimParm;

   InventDim           invDim;

   Qty                 availPhys;

   invDim.InventLocationId = 'INVENTLOCATIONID';

   invDim = InventDim::findOrCreate(invDim);

   invDimParm.initFromInventDim(InventDim::find(invDim.inventDimId));

   availPhys = InventSum::findSum("ITEMID",invDim,invDimParm).availPhysical();

   info(strfmt("availPhys:%1 ",availPhys));

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InventDim           inventDim;

   InventDimParm       inventDimParm;

   InventOnhand        inventOnhand;

  

   inventDim.InventLocationId = 'Yourwarehouse';

   inventDimParm.initFromInventDim(inventDim);

   inventOnhand = InventOnhand::newParameters('Youritem', inventDim, inventDimParm);

   info(strfmt("Available Physical: %1", inventOnhand.availPhysical()));