Insert the specified text in all selected lines, always
        at the same column position.

def commit(self):
        """
        Insert the specified text in all selected lines, always
        at the same column position.
        """

        # Get the number of lines and columns in last line.
        last_line, last_col = self.qteWidget.getNumLinesAndColumns()

        # If this is the first ever call to this undo/redo element
        # then backup the current cursor- and marker position because
        # both will be required for the redo operation.
        if self.cursorPos is None:
            # Get the default marker and ensure it points to a
            # valid location inside the document.
            self.markerPos = self.qteWidget.qteGetMark()
            if self.markerPos is None:
                return
            if not self.qteWidget.isPositionValid(*self.markerPos):
                return

            # Backup the current cursor and marker position; swap
            # one for the other if necessary to ensure the marker
            # comes first.
            self.cursorPos = self.qteWidget.getCursorPosition()
            if self.cursorPos[0] < self.markerPos[0]:
                self.cursorPos, self.markerPos = self.markerPos, self.cursorPos

        # Insert the specified string at the same position in every line
        # in between the mark and the cursor (inclusive).
        col = min((self.markerPos[1], self.cursorPos[1]))
        for line in range(self.markerPos[0], self.cursorPos[0] + 1):
            self.baseClass.insertAt(self.text, line, col)

        self.qteWidget.setCursorPosition(*self.cursorPos)