Python Module not working in Python based extension

Hallo,
I tried to get a Python Module named Ibis working in a new Python Extension node. So I installed everything and got the example working from Create a New Python based KNIME Extension
For my environment I had to adjust the conda create

conda create -n my_python_env python=3.11 knime-python-base=5.3 knime-extension=5.3 ibis-duckdb -c knime -c conda-forge 

But when inserting the following lines somewhere in the example to get Ibis in action:

import ibis
t = ibis.memtable([{"a": 1}, {"a": 2}]) 

I got an Error:

AttributeError: module 'ibis' has no attribute 'memtable'

When I looked into the module with LOGGER.warning(dir(ibis)) the module was loaded, but only the _ -functions were available.
Actually in a Python Script node it works.