// 打印 jupyter notebook
jupyter nbconvert hw.ipynb --to pdf// 打开notebook指令：
python3 -m IPython notebook添加 channel (清华镜像)：
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main
conda config --set show_channel_urls yes去除 channel:
conda config --remove channels https://mirrors.tuna.tsinghua.edu.cn/tensorflow/linux/cpu/查看当前 channels:
conda config --show channels换回默认源:
conda config --remove-key channels// conda 打开环境
conda activate eecs545