Not working: just seeing the json text of the .ipynb

Hello,

I tried to install/uninstall and re-install that package and the only thing that I can see when I open a .ipynb is the json content:

```
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Neural Field"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"blabla.\n",
"\n",
"blabla\n",
"\n",
"~~~\n",
"python NeuralField.py\n",
"~~~"
]
},
....
```

Did I miss something?