The previous dev has left a really strange `not x is None` yoda condition in the code:

```
>>> x = None
>>> not x is None
False
>>> x = 1
>>> not x is None
True

```

After some testing, I seem the same output as `x is not None`.

```
>>> x = None
>>> not x is None
False
>>> x is not None
False
>>> x = 1
>>> not x is None
True
>>> x is not None
True

```

**Is `not x is None` always equivalent to `x is not None`?** 

To break down the condition, **is it `not (x is None)` or `(not x) is None`**? Or will the former always be equivalent to the latter?