def _get_stock_price(self, init_stock_price):
    output = ((self.sigma * self.brownian_motion) - ((0.5 * (self.sigma ** 2)) * self.time_grid))
    return (init_stock_price * np.exp(output))
def _get_stock_price(self, init_stock_price):
    output = ((self.sigma * self.brownian_motion) - ((0.5 * (self.sigma ** 2)) * self.time_grid))
    return (init_stock_price * np.exp(output))