Python: LGTM.com - false positive 'Call to a non-callable of builtin-class module.'

**Description of the false positive**
When using `dask.delayed` we get a false positive 'Call to a non-callable of builtin-class module.'
The [query description](https://lgtm.com/rules/7860087/), states:
> The callable(object) builtin function determines if an object is callable or not.

So here is a minimal example using `callable` on the objects in question.

```python
In [1]: import dask

In [2]: obj1 = dask.delayed(lambda x: x*2)

In [3]: type(obj1)
Out[3]: dask.delayed.DelayedLeaf

In [4]: callable(obj1)
Out[4]: True

In [5]: obj2 = dask.delayed(lambda x: x*2)(1)

In [6]: type(obj2)
Out[6]: dask.delayed.Delayed

In [7]: callable(obj2)
Out[7]: True

In [8]: obj2.compute()
Out[8]: 2
```

**URL to the alert on the project page on LGTM.com**

https://lgtm.com/projects/g/glotaran/pyglotaran/snapshot/f6f2e68064ae770c5c31535660f5428bbc015fbd/files/glotaran/analysis/residual_calculation.py?sort=name&dir=ASC&mode=heatmap#x790ea2e7893621f4:1