When instanciating `Steem()` you can pass an array of wif keys:
```python
steem = Steem(keys=[wif1, wif2, wif3]
```

of you install the keys into the library-internal wallet using pison
```
piston addkey
```
then you don't need to deal with keys in the script at all but need to provide the masterpassword for the wallet either in the terminal-prompt, or in the environmental variable `UNLOCK`