def onShortcutUnindentWithBackspace(self):
        """Backspace pressed, unindent
        """
        assert self._qpart.textBeforeCursor().endswith(self.text())

        charsToRemove = len(self._qpart.textBeforeCursor()) % len(self.text())
        if charsToRemove == 0:
            charsToRemove = len(self.text())

        cursor = self._qpart.textCursor()
        cursor.setPosition(cursor.position() - charsToRemove, QTextCursor.KeepAnchor)
        cursor.removeSelectedText()
def test_impl(n):
            df = pd.DataFrame({'A': np.ones(n), 'B': np.random.ranf(n)})
            df.A.fillna(5.0, inplace=True)
            DF = df.A.fillna(5.0)
            s = DF.sum()
            m = df.A.mean()
            v = df.A.var()
            t = df.A.std()
            Ac = df.A.cumsum()
            return Ac.sum() + s + m + v + t