"Using Debugging Helpers]" shows

putCallItem(self, name, value, func, *args) - Uses the native debugger backend to place the function call func on the value specified by value and output the resulting item

However the signature for the real implementation of putCallItem() as found in dumper.py looks like this:

def putCallItem(self, name, rettype, value, func, *args):

So "rettype" is missing.

https://doc-snapshots.qt.io/qtcreator-9.0/creator-debugging-helpers.html#dumper-class