opt_dict is an dictionary with 5 elements: '1' for 'bold', '4' for 'underscore', '5' for 'blink', '7' for 'reverse',
opt_dict = { 'bold' : '1' , 'underscore' : '4' , 'blink' : '5' , 'reverse' : '7' , 'conceal' : '8' }