def blank(self, colorPair):
    'Clear the window.'
    for i in range(self.rows):
        self.addStr(i, 0, (' ' * self.cols), colorPair)
Clear the window.
def blank(self, colorPair):
    
    for i in range(self.rows):
        self.addStr(i, 0, (' ' * self.cols), colorPair)