docs: function acquireContext(item, config) {
  		if (typeof item === 'string') {
  			item = document.getElementById(item);
  		} else if (item.length) {
  			// Support for array based queries (such as jQuery)
  			item = item[0];
  		}
  
  		if (item && item.canvas) {
  			// Support for any object associated to a canvas (including a context2d)
  			item = item.canvas;
  		}
  
  		if (item instanceof HTMLCanvasElement) {
  			// To prevent canvas fingerprinting, some add-ons undefine the getContext
  			// method, for example: https://github.com/kkapsner/CanvasBlocker
  			// https://github.com/chartjs/Chart.js/issues/2807
  			var context = item.getContext && item.getContext('2d');
  			if (context instanceof CanvasRenderingContext2D) {
  				initCanvas(item, config);
  				return context;
  			}
  		}
  
  		return null;
  	}