!505 unify code formats notebook for master

Merge pull request !505 from lvmingfu/master

tutorials/notebook/mindinsight/calculate_and_datagraphic.ipynb

@@ -35,8 +35,8 @@
     "\n",
     "从以下网址下载，并将数据包解压后放在Jupyter的工作目录下。\n",
     "\n",
-    "- 训练数据集：{\"http://yann.lecun.com/exdb/mnist/train-images-idx3-ubyte.gz\",\"http://yann.lecun.com/exdb/mnist/train-labels-idx1-ubyte.gz\"}\n",
-    "- 测试数据集：{\"http://yann.lecun.com/exdb/mnist/t10k-images-idx3-ubyte.gz\",\"http://yann.lecun.com/exdb/mnist/t10k-labels-idx1-ubyte.gz\"}\n",
+    "- 训练数据集：{\"<http://yann.lecun.com/exdb/mnist/train-images-idx3-ubyte.gz>\",\"<http://yann.lecun.com/exdb/mnist/train-labels-idx1-ubyte.gz>\"}\n",
+    "- 测试数据集：{\"<http://yann.lecun.com/exdb/mnist/t10k-images-idx3-ubyte.gz>\",\"<http://yann.lecun.com/exdb/mnist/t10k-labels-idx1-ubyte.gz>\"}\n",
     "\n",
     "可执行下面代码查看Jupyter的工作目录。"
    ]