"ImportError: libcublas.so.9.1" but I have cuda 9.0

Hello there,
I have only Cuda 9.0 installed right now, but I had Cuda 9.1 installed in the past.
How to overcome this?

for example:

import dlib

ImportError: libcublas.so.9.1: cannot open shared object file: No such file or directory

that’s obvious because only 9.0 is installed.

Similar results if I run libcublas examples.

Uninstall, purge, and so on does not resolve this issue.

solved reinstalling also the Cuda 9.1 library.