Is this a bug? 
Author: ghost
Pull request: no

Hello, 
I tried to import this: 

`from transformers import AdamW, get_linear_schedule_with_warmup`
but got error : model not found
but when i did this, it worked: 
```
from transformers import AdamW
from transformers import WarmupLinearSchedule as get_linear_schedule_with_warmup
```
however when I set the scheduler like this : 
```
scheduler = get_linear_schedule_with_warmup(optimizer, num_warmup_steps=args.warmup_steps, num_training_steps=t_total) 
```
I got this error : 
```
__init__() got an unexpected keyword argument 'num_warmup_steps'
```

Comments:
duplicated 
https://github.com/huggingface/transformers/issues/1837#issue-523145270

I checked the other comment but did not work. Any idea ? 
```
__init__() got an unexpected keyword argument 'num_warmup_steps'
```


Hi, could you specify which versions of Python and Transformers is your environment running on?

Thanks
```
python: 3.6.8
Transformers: 2.1.1
```


Did you install transformers from source or from pypi?

Could you try installing from source and telling me if it fixes your problem?

Thanks it worked

worked with building from the source and this 
```
from transformers import AdamW,get_linear_schedule_with_warmup
```

Great to hear!

whats the meaning of installing from source ,i am a little bit confused. could you please tell me ,thank you.
i've tried   'pip install git+https://github.com/huggingface/transformers' or pip install transformers 
or pip install pytorhc-transformers. But they all doesn't work.

> Hello,
> I tried to import this:
> 
> `from transformers import AdamW, get_linear_schedule_with_warmup`
> but got error : model not found
> but when i did this, it worked:
> 
> ```
> from transformers import AdamW
> from transformers import WarmupLinearSchedule as get_linear_schedule_with_warmup
> ```
> 
> however when I set the scheduler like this :
> 
> ```
> scheduler = get_linear_schedule_with_warmup(optimizer, num_warmup_steps=args.warmup_steps, num_training_steps=t_total) 
> ```
> 
> I got this error :
> 
> ```
> __init__() got an unexpected keyword argument 'num_warmup_steps'
> ```

can you kindly tell me how to install from source.

@TLCFYBJJHYYSND See https://github.com/huggingface/transformers#from-source

In order to install Transformers library, you have to open your command line and enter:
```
pip install git+https://github.com/huggingface/transformers.git
```
> > Hello,
> > I tried to import this:
> > `from transformers import AdamW, get_linear_schedule_with_warmup`
> > but got error : model not found
> > but when i did this, it worked:
> > ```
> > from transformers import AdamW
> > from transformers import WarmupLinearSchedule as get_linear_schedule_with_warmup
> > ```
> > 
> > 
> > however when I set the scheduler like this :
> > ```
> > scheduler = get_linear_schedule_with_warmup(optimizer, num_warmup_steps=args.warmup_steps, num_training_steps=t_total) 
> > ```
> > 
> > 
> > I got this error :
> > ```
> > __init__() got an unexpected keyword argument 'num_warmup_steps'
> > ```
> 
> can you kindly tell me how to install from source.

Thanks for that, it really works!!!