Repository: snap-stanford/ogb
Issue: ImportError: cannot import name 'PygGraphPropPredDataset' from 'ogb.graphproppred' 
Root cause: Documentation Deficiency

I just installed the package with
`pip3 install ogb`
and tried to run the small testscript:
```

from ogb.graphproppred import PygGraphPropPredDataset
from torch_geometric.data import DataLoader

# Download and process data at './dataset/ogbg_molhiv/'
dataset = PygGraphPropPredDataset(name="ogbg-molhiv", root='dataset/')

split_idx = dataset.get_idx_split()
train_loader = DataLoader(dataset[split_idx["train"]], batch_size=32, shuffle=True)
valid_loader = DataLoader(dataset[split_idx["valid"]], batch_size=32, shuffle=False)
test_loader = DataLoader(dataset[split_idx["test"]], batch_size=32, shuffle=False)

```

However I receive the following:
```

Connected to pydev debugger (build 203.7148.72)
Traceback (most recent call last):
  File "/snap/pycharm-community/226/plugins/python-ce/helpers/pydev/pydevd.py", line 1477, in _exec
    pydev_imports.execfile(file, globals, locals)  # execute the script
  File "/snap/pycharm-community/226/plugins/python-ce/helpers/pydev/_pydev_imps/_pydev_execfile.py", line 18, in execfile
    exec(compile(contents+"\n", file, 'exec'), glob, loc)
  File "/home/tue/.config/JetBrains/PyCharmCE2020.3/scratches/scratch_2.py", line 1, in <module>
    from ogb.graphproppred import PygGraphPropPredDataset
ImportError: cannot import name 'PygGraphPropPredDataset' from 'ogb.graphproppred' (/home/tue/.local/lib/python3.8/site-packages/ogb/graphproppred/__init__.py)
python-BaseException

Process finished with exit code 130 (interrupted by signal 2: SIGINT)
```

I'm using python 3.8 and should have all the required packages, as far as I can see.

```
pip3 list
Package                  Version             
------------------------ --------------------
apt-clone                0.2.1               
apturl                   0.5.2               
ase                      3.21.1              
beautifulsoup4           4.8.2               
biopython                1.78                
blinker                  1.4                 
Brlapi                   0.7.0               
certifi                  2019.11.28          
chardet                  3.0.4               
Click                    7.0                 
colorama                 0.4.3               
command-not-found        0.3                 
configobj                5.0.6               
cryptography             2.8                 
cupshelpers              1.0                 
cycler                   0.10.0              
dbus-python              1.2.16              
decorator                4.4.2               
defer                    1.0.6               
distro                   1.4.0               
entrypoints              0.3                 
googledrivedownloader    0.4                 
grpcio                   1.16.1              
h5py                     3.2.1               
httplib2                 0.14.0              
idna                     2.8                 
ifaddr                   0.1.6               
IMDbPY                   6.8                 
indicator-sound-switcher 2.3.5.2             
isal                     0.5.0               
isodate                  0.6.0               
Jinja2                   2.11.3              
joblib                   1.0.1               
kazam                    1.5.3               
keyring                  18.0.1              
kiwisolver               1.3.1               
launchpadlib             1.10.13             
lazr.restfulclient       0.14.2              
lazr.uri                 1.0.3               
littleutils              0.2.2               
llvmlite                 0.35.0              
louis                    3.12.0              
macaroonbakery           1.3.1               
Mako                     1.1.0               
MarkupSafe               1.1.0               
matplotlib               3.3.4               
nemo-emblems             4.8.1               
netifaces                0.10.4              
networkx                 2.5                 
nose                     1.3.7               
numba                    0.52.0              
numpy                    1.20.1              
oauthlib                 3.1.0               
ogb                      1.2.6               
onboard                  1.4.1               
outdated                 0.2.0               
packaging                20.3                
PAM                      0.4.2               
pandas                   1.2.3               
pexpect                  4.6.0               
Pillow                   7.0.0               
pip                      20.0.2              
protobuf                 3.6.1               
psutil                   5.5.1               
pycairo                  1.16.2              
pycrypto                 2.6.1               
pycups                   1.9.73              
pycurl                   7.43.0.2            
PyGObject                3.36.0              
PyICU                    2.4.2               
pyinotify                0.9.6               
PyJWT                    1.7.1               
pymacaroons              0.13.0              
PyNaCl                   1.3.0               
pyparsing                2.4.6               
pyparted                 3.11.2              
pyRFC3339                1.1                 
python-apt               2.0.0+ubuntu0.20.4.4
python-dateutil          2.8.1               
python-debian            0.1.36ubuntu1       
python-louvain           0.15                
python-xapp              2.0.2               
python-xlib              0.23                
pytz                     2019.3              
pyxdg                    0.26                
PyYAML                   5.3.1               
rdflib                   5.0.0               
reportlab                3.5.34              
requests                 2.22.0              
requests-file            1.4.3               
requests-unixsocket      0.2.0               
scikit-learn             0.24.1              
scipy                    1.6.1               
screen-resolution-extra  0.0.0               
SecretStorage            2.3.1               
setproctitle             1.1.10              
setuptools               45.2.0              
simplejson               3.16.0              
six                      1.14.0              
soupsieve                1.9.5               
systemd-python           234                 
threadpoolctl            2.1.0               
tinycss2                 1.0.2               
tldextract               2.2.1               
torch                    1.8.0               
torch-geometric          1.6.3               
torchaudio               0.8.0               
torchvision              0.9.0               
tqdm                     4.59.0              
typing-extensions        3.7.4.3             
ubuntu-advantage-tools   20.3                
ubuntu-drivers-common    0.0.0               
ufw                      0.36                
Unidecode                1.1.1               
urllib3                  1.25.8              
wadllib                  1.3.3               
webencodings             0.5.1               
wheel                    0.34.2              
xkit                     0.0.0               
xopen                    1.1.0               
zeroconf                 0.24.4    
```

It seems that you do not have all required packages installed in order to run PyG. Please follow the installation procedure described [here](https://github.com/rusty1s/pytorch_geometric#installation) for installing PyG. Alternatively, you can access OGB datasets via
```
from ogb.graphproppred import GraphPropPredDataset
```
without any additional library requirements.

> 似乎您没有安装所有必需的软件包才能运行PyG。请按照[此处](https://github.com/rusty1s/pytorch_geometric#installation)描述的安装步骤安装PyG。或者，您可以通过以下方式访问OGB数据集：
> 
> ```
> from ogb.graphproppred import GraphPropPredDataset
> ```
> 
> 无需任何其他库要求。

Hello, I can't find a file named "ogbn arXiv" in graphproppreddataset. Which file does this file correspond to in graphproppreddataset?



ogbn-arxiv is a node classification dataset.

```python
from ogb.nodeproppred import NodePropPredDataset
```