<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def format_result(line, line_num, txt):
 """ highlight the search result """

    
    return '&nbsp;&nbsp;' + str(line_num) + ': ' + line.replace(txt, '<span style="background-color: #FFFF00">' + txt + '</span>')