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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 fix_w391(self, _):
 """Remove trailing blank lines."""

        blank_count = 0
        for line in reversed(self.source):
            line = line.rstrip()
            if line:
                break
            else:
                blank_count += 1

        original_length = len(self.source)
        self.source = self.source[:original_length - blank_count]
        return range(1, 1 + original_length)