'Normalize entire dataset (delta_x, delta_y) by the scaling factor.'

def normalize(self, scale_factor=None):

    if (scale_factor is None):
        scale_factor = self.calculate_normalizing_scale_factor()
    self.scale_factor = scale_factor
    for i in range(len(self.strokes)):
        self.strokes[i][:, 0:2] /= self.scale_factor
