The "get" function is not implemented in the Dict.

in gpython
``` python
>>>> d ={'a' : 1}
>>>> d.get('a')
Traceback (most recent call last):
 File "test.py", line 13, in <module>
 FIXME line of source goes here
AttributeError: "'dict' has no attribute 'get'"
2019/09/29 16:24:04 AttributeError: "'dict' has no attribute 'get'"
```

in python
``` python
>>>> d ={'a' : 1}
>>>> d.get('a')
1
```