NeXus file in tutorial does not validate

[prjemian]

Tested the NeXus files in the Higher Dimensional Data tutorial for validation to the NeXus standard and found one consistent ERROR using the punx program.

(bluesky_2020_5) jemian@wow ~/.../Bluesky/nexus_data $ punx val 512-512-128-5.0-20.0-00286-0360.nxs | grep ERROR
/entry@default                                                  ERROR  value of @default                    not found: /entry/data
ERROR    1     violates NeXus specification                                -10000000

The value of that attribute should be changed to one of these three groups:

(bluesky_2020_5) jemian@wow ~/.../Bluesky/nexus_data $ punx tree -a -m 0 512-512-128-5.0-20.0-00286-0360.nxs | grep NXdata
/home/beams/JEMIAN/.conda/envs/bluesky_2020_5/lib/python3.7/site-packages/punx/h5tree.py:155: H5pyDeprecationWarning: dataset.value has been deprecated. Use dataset[()] instead.
  value = " = %s" % str(dset.value)
    sasdata_singleimg:NXdata
    sasdata_singleimg_remesh:NXdata
    sasdata_singleimg_unwrap:NXdata

such as default="sasdata_singleimg"

For explanation how to choose this value, see: https://manual.nexusformat.org/classes/base_classes/NXentry.html#index-2

The default attribute is used to enable one of the core NeXus motivations: simple plotting.