ModuleNotFoundError: No module named 'transformers'
Author: JadeInTheSky
Pull request: no

## Environment info
<!-- You can run the command `transformers-cli env` and copy-and-paste its output below.
     Don't forget to fill out the missing fields in that output! -->
transformers-cliv: command not found


- `transformers` version: 4.8.2
- Platform: Ubuntu (20.04) with KDE desktop
- Python version: 3.9
- PyTorch version (GPU?): 1.9.0, (not running on GPU)
- Tensorflow version (GPU?):  2.5.0 (not running on GPU)
- Using GPU in script?: no
- 
- Using distributed or parallel set-up in script?: distributed

### Who can help
<!-- Your issue will be replied to more quickly if you can figure out the right person to tag with @
 If you know how to use git blame, that is the easiest way, otherwise, here is a rough guide of **who to tag**.
 Please tag fewer than 3 people.

Models:

- gpt2: @patrickvonplaten, @LysandreJik 

Library:

- text generation: @patrickvonplaten

 -->

## Information

Model I am using (Bert, XLNet ...): DialoGPT
I tried uninsall transformes, reinstalling it, installing version 3.5.0 but all doesnt work

The problem arises when using:
* [ ] the official example scripts: (give details below):
* [ ]  Script is basic exemple of DialoGPT; { 


```python
from transformers import AutoModelForCausalLM, AutoTokenizer
import torch


tokenizer = AutoTokenizer.from_pretrained("microsoft/DialoGPT-large")
model = AutoModelForCausalLM.from_pretrained("microsoft/DialoGPT-large")

# Let's chat for 5 lines
for step in range(5):
    # encode the new user input, add the eos_token and return a tensor in Pytorch
    new_user_input_ids = tokenizer.encode(input(">> User:") + tokenizer.eos_token, return_tensors='pt')

    # append the new user input tokens to the chat history
    bot_input_ids = torch.cat([chat_history_ids, new_user_input_ids], dim=-1) if step > 0 else new_user_input_ids

    # generated a response while limiting the total chat history to 1000 tokens, 
    chat_history_ids = model.generate(bot_input_ids, max_length=1000, pad_token_id=tokenizer.eos_token_id)

    # pretty print last ouput tokens from bot
    print("DialoGPT: {}".format(tokenizer.decode(chat_history_ids[:, bot_input_ids.shape[-1]:][0], skip_special_tokens=True)))
```

error: 
(base) hest1a@latitude-ubuntu:~/ProjectChristina$ python3.9 christina.py 
Traceback (most recent call last):
  File "/home/hest1a/ProjectChristina/christina.py", line 1, in <module>
    from transformers import AutoModelForCausalLM, AutoTokenizer
ModuleNotFoundError: No module named 'transformers'


]}
## To reproduce

Steps to reproduce the behavior:

1. run the code (python3.9 code.py)

<!-- If you have code snippets, error messages, stack traces please provide them here as well.
     Important! Use code tags to correctly format your code. See https://help.github.com/en/github/writing-on-github/creating-and-highlighting-code-blocks#syntax-highlighting
     Do not use screenshots, as they are hard to read and (more importantly) don't allow others to copy-and-paste your code.-->

## Expected behavior

when running the code, I expect to start the basic DialoGPT chat program..
<!-- A clear and concise description of what you would expect to happen. -->


Comments:
I fixed it, 

it appears that using pip install (libraries) ubuntu installed the python 2 version of the required module..
uninstalling them and using 
``` 
pip3.9 install transformers 
```
installs the 3.9 versions of the module and allows the code to run smoothly..