<type 'exceptions.TypeError'> every time when add asUser params 

hackpad.py

```
  for key in post_data.keys():
    params[key] = post_data[key]

  hackpad_api = OAuth1Session(**params)
```

but whenever params more than 2 parameter 
Oauth1Session(**parms) threws the error

<type 'exceptions.TypeError'>

Am I doing this wrong?
