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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def guess_lexer_using_filename(file_name, text):
 """Guess lexer for given text, limited to lexers for this file's extension. Returns a tuple of (lexer, accuracy). """


    lexer, accuracy = None, None

    try:
        lexer = custom_pygments_guess_lexer_for_filename(file_name, text)
    except SkipHeartbeat as ex:
        raise SkipHeartbeat(u(ex))
    except:
        log.traceback(logging.DEBUG)

    if lexer is not None:
        try:
            accuracy = lexer.analyse_text(text)
        except:
            log.traceback(logging.DEBUG)

    return lexer, accuracy