def add_feature(self, x: np.ndarray)->np.ndarray: ''' add one feature to the data input Parameters: x is the data input. x is one dimensional or two dimensional numpy array. Return: updated data input with the last column of x being 1s. ''' if len(x.shape) == 1: # if x is one dimensional, convert it to be two dimensional x = x.reshape((1, -1)) #### write your code below #### #### write yoru codel return X。请帮我完成需要填写的代码

您好，针对您的代码，我来帮您完成需要填写的代码：

# add a column of ones to the input data
ones = np.ones((x.shape[0], 1))
X = np.hstack((x, ones))

以上代码会在输入数据的最后一列添加一个全为1的列，以增加模型的灵活性和表达能力。

希望对您有帮助！