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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 scan(src):
 """ Scan scss from string and return nodes. """

        assert isinstance(src, (unicode_, bytes_))
        try:
            nodes = STYLESHEET.parseString(src, parseAll=True)
            return nodes
        except ParseBaseException:
            err = sys.exc_info()[1]
            print(err.line, file=sys.stderr)
            print(" " * (err.column - 1) + "^", file=sys.stderr)
            print(err, file=sys.stderr)
            sys.exit(1)