ImportError: No module named fire.

I run the command 
`pip3 install fire` and then run the hello.py script shown in the tutorial. This is the error message that I get: 

```
bluebee@bbench:~$ python hello.py
Traceback (most recent call last):
  File "hello.py", line 1, in <module>
    import fire 
ImportError: No module named fire.
```

