Iris changes bypass `Nc4DatasetLike.filepath()`

[trexfeathers]

The change: SciTools/iris@03a5e72

Before/After	How Iris acquires the NetCDF file name
Before the change	Dataset.filepath() exclusively
After the change	Also Variable.group().filepath() 1

Approach	Class that represents dataset	Class implements .filepath()?
to_iris()	Nc4DatasetLike	Yes ✔
Nc4VariableLike.group()	NcData	No ❌

A fix is not urgent, as this is de-risked by SciTools/iris#6495. And a fix might be made unnecessary by #122?

Footnotes

1. .group() returns the Dataset ↩

[trexfeathers]

Wait a minute, you're not a NetCDF4 object, you're an NcData object!