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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 extraSelections(self, qpart, block, columnIndex):
 """List of QTextEdit.ExtraSelection's, which highlighte brackets """

        blockText = block.text()

        if columnIndex < len(blockText) and \
             blockText[columnIndex] in self._ALL_BRACKETS and \
             qpart.isCode(block, columnIndex):
            return self._highlightBracket(blockText[columnIndex], qpart, block, columnIndex)
        elif columnIndex > 0 and \
           blockText[columnIndex - 1] in self._ALL_BRACKETS and \
           qpart.isCode(block, columnIndex - 1):
            return self._highlightBracket(blockText[columnIndex - 1], qpart, block, columnIndex - 1)
        else:
            self.currentMatchedBrackets = None
            return []