code: def get_font(self, values):
          
          font_key = values
          f = self.FONT_FACTORY.get(font_key, None)
          if f is None:
              f = xlwt.Font()
              for attr, value in values:
                  f.__setattr__(attr, value)
              self.FONT_FACTORY[font_key] = f
          return f
docs: 'height' 10pt = 200, 8pt = 160