Cannot Import a python Module from a package that is installed in Ubuntu

Before I talk about the problem, I cannot use pip directly in ubuntu, I have to set a python virtual environment first. whenever I do that outside the environment I get this message :

error: externally-managed-environment× This environment is externally managed╰─> To install Python packages system-wide, try apt install    python3-xyz, where xyz is the package you are trying to    install.    If you wish to install a non-Debian-packaged Python package,    create a virtual environment using python3 -m venv path/to/venv.    Then use path/to/venv/bin/python and path/to/venv/bin/pip. Make    sure you have python3-full installed.    If you wish to install a non-Debian packaged Python application,    it may be easiest to use pipx install xyz, which will manage a    virtual environment for you. Make sure you have pipx installed.    See /usr/share/doc/python3.12/README.venv for more information.note: If you believe this is a mistake, please contact your Python installation or OS distribution provider. You can override this, at the risk of breaking your Python installation or OS, by passing --break-system-packages.hint: See PEP 668 for the detailed specification.

I installed a package called mamba-ssm using pip. and I am using command line to run a python script that imports a module from mamba ssm like this :

`from mamba_ssm.ops.triton.ssd_combined import mamba_chunk_scan_combined`

but when I run the script I get this error message :ModuleNotFoundError: No module named mamba_ssm.ops.triton.ssd_combined

But when I run python in the terminal and import the module it gets imported.

I tried :export PYTHONPATH=home/venv/lib/python3.12/site-packages/mamba_ssm:$PYTHONPATHthen running my code.

I tried executing the code using python of the venv I created :/home/venv/bin/python

added from mamba_ssm.ops.triton.ssd_combined import mamba_chunk_scan_combined to __init__py

nothing works.