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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 __writeDocstring(self):
 """ Runs eternally, dumping out docstring line batches as they get fed in. Replaces original batches of docstring lines with modified versions fed in via send. """

        while True:
            firstLineNum, lastLineNum, lines = (yield)
            newDocstringLen = lastLineNum - firstLineNum + 1
            while len(lines) < newDocstringLen:
                lines.append('')
            # Substitute the new block of lines for the original block of lines.
            self.docLines[firstLineNum: lastLineNum + 1] = lines