A required or given text value must not be blank ("" or whitespace only): GENESIS reads an empty parameter as "no filter", so a blank filter would silently return unfiltered data. A non-string counts as missing.
""
A required or given text value must not be blank (
""or whitespace only): GENESIS reads an empty parameter as "no filter", so a blank filter would silently return unfiltered data. A non-string counts as missing.