major and annoying differences between module versions of Pythons JSON Library

gistfile1.txt

Two versions of the same library behave completely different :-/

the PI

```
Python 3.4.2 (default, Oct 19 2014, 13:31:11) 
[GCC 4.9.1] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import json
>>> try:
...     json.loads('notjson')
... except json.JSONDecodeError:
...    print("didn't work")
... 
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "/usr/lib/python3.4/json/__init__.py", line 318, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python3.4/json/decoder.py", line 343, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib/python3.4/json/decoder.py", line 361, in raw_decode
    raise ValueError(errmsg("Expecting value", s, err.value)) from None
ValueError: Expecting value: line 1 column 1 (char 0)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 3, in <module>
AttributeError: 'module' object has no attribute 'JSONDecodeError'
>>> 
```


the Mac:

```
Python 3.5.0 (default, Sep 23 2015, 04:41:38) 
[GCC 4.2.1 Compatible Apple LLVM 7.0.0 (clang-700.0.72)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import json
>>> try:
...     json.loads("notjson")
... except json.JSONDecodeError:
...     print("didn't work")
... 
didn't work
>>> 
```

JSONDecodeError was introduced in 3.5
https://docs.python.org/3/whatsnew/3.5.html#json

Use ValueError in older versions instead.