GPU support Installation

I have GPU and CUDA, CuDNN, and NCCL. My OS is Ubuntu 16.04, I followed this tutorial to install Coffe2 with GPU support (
conda install -c caffe2 caffe2-cuda9.0-cudnn7
) and the installation finished successfully but this command: python2 -c ‘from caffe2.python import workspace; print(workspace.NumCudaDevices())’

returns: WARNING:root:This caffe2 python run does not have GPU support. Will run in CPU only mode.
WARNING:root:Debug message: cannot open shared object file: No such file or directory
Segmentation fault (core dumped)
Any Idea how can I solve it??