Frm.make_methods Help to understand this fuonction

I am reading item.js file in ERPNext. Here I found frm.make_methods this method. Full code is

		frm.make_methods = {
			'Sales Order': () => {
				open_form(frm, "Sales Order", "Sales Order Item", "items");
			},
			'Delivery Note': () => {
				open_form(frm, "Delivery Note", "Delivery Note Item", "items");
			},
			'Sales Invoice': () => {
				open_form(frm, "Sales Invoice", "Sales Invoice Item", "items");
			},
			'Purchase Order': () => {
				open_form(frm, "Purchase Order", "Purchase Order Item", "items");
			},
			'Purchase Receipt': () => {
				open_form(frm, "Purchase Receipt", "Purchase Receipt Item", "items");
			},
			'Purchase Invoice': () => {
				open_form(frm, "Purchase Invoice", "Purchase Invoice Item", "items");
			},
			'Material Request': () => {
				open_form(frm, "Material Request", "Material Request Item", "items");
			},
			'Stock Entry': () => {
				open_form(frm, "Stock Entry", "Stock Entry Detail", "items");
			},
		};

Can anyone here please help to understand what this method actually do?