Why didn't this animation be executed?

Why can"t custom animations for jq be performed? Why doesn"t the animation sequence of fx1 execute? That is, width added 50px MagneHeigh animation did not execute.
$(".io"). Animate ({"width": "+ = 50px"}, {duration:3000,function () {$(this) .dequeue ("fx1");}});
$(".io"). Queue ("fx1", function () {console.log ("over"); $(this) .dequeue ("fx1"); $(".io"). Animate ({"height": "+ = 50px"}, {duration:3000,function () {$(this). Dequeue ();});});

May.22,2021
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