qgis - Creating Selection MapTool in PyQgis Custom Application

I'm developing a custom GIS application using PyQgis API.

How can I let the user select features on the map using Maptools? I would like to replicate the select feature there in Qgis to make the selection on click of a button. My understanding is to use layer.selectedFeatures() function , but I am not sure of how to add the Selection Maptool to the mapcanvas and toolbar.