Improve check for empty values for XML-based values
Improve check for empty values for XML-based values

See
https://hg.python.org/cpython/file/43f27e69bc29/Lib/xml/etree/ElementTree.py#l231
for details

opendata-swiss/ckanext-geocat,opendata-swiss/ckanext-geocat,ogdch/ckanext-geocat,ogdch/ckanext-geocat