def yview_scroll(self, *L):
        # change by frank gao for attach scrollbar 11/11/2010
        """Adjust the view in the window up or down according to number and
        what. The 'number' parameter must be an integer. The 'what' parameter
        must be either units or pages or an abbreviation of one of these.

        If 'what' is units, the view adjusts up or down by number cells; if it
        is pages then the view adjusts by number screenfuls.
        If 'number' is negative then earlier elements become visible; if it
        is positive then later elements become visible. """
        #self.tk.call(self._w, 'yview', 'scroll', number, what)
        op, howMany = L[0], L[1]
        if op is 'scroll':
            units = L[2]
            self.tk.call(self._w, 'yview', 'scroll', howMany, units)
        elif op == 'moveto':
            self.tk.call(self._w, 'yview', 'moveto', howMany)
dataset/ETHPy150Open Arelle/Arelle/arelle/TkTableWrapper.py/Table.yview_scroll/operator `==` -> `is`