def save_as_png(self, filename, width=<NUM_LIT>, height=<NUM_LIT>, render_time=<NUM_LIT:1>):
self.driver.set_window_size(width, height)<EOL>self.driver.get('<STR_LIT>'.format(<EOL>path=os.getcwd(), filename=filename + "<STR_LIT>"))<EOL>time.sleep(render_time)<EOL>self.driver.save_screenshot(filename + "<STR_LIT>")<EOL>
Open saved html file in an virtual browser and save a screen shot to PNG format.