title: Cannot import python package in jupyter
body: <p>I have the following problem. I installed rpy2 via <code>conda install rpy2</code> in my virtualenv. Now, I can import this package in terminal if I run</p>
  
  <pre><code>&gt;&gt;&gt; python
  &gt;&gt;&gt; import rpy2
  </code></pre>
  
  <p>However, if I try to import rpy2 in jupyter notebook I get an error <code>ModuleNotFoundError: No module named 'rpy2'</code>. If I run the following code</p>
  
  <pre><code>import sys
  print(sys.prefix)
  </code></pre>
  
  <p>I get <code>/anaconda3</code>. Also if I do the same via terminal: <code>python-&gt;import sys -&gt; print(sys.prefix)</code> I get <code>/anaconda3/envs/work_python36</code>. If I run <code>which python</code> in terminal I obtain: <code>/anaconda3/envs/work_python36/bin/python</code>. I tried to change <code>PYTHONPATH</code> using export, but it did not work. If anyone knows how to solve this problem, please, tell me.</p>
  
  <p>I also printed the following <code>conda info -a</code></p>
  
  <pre><code>active environment : work_python36
  active env location : /anaconda3/envs/work_python36
          shell level : 1
     user config file : /Users/alex/.condarc
  populated config files : 
        conda version : 4.5.12
  conda-build version : 3.10.5
       python version : 3.6.5.final.0
     base environment : /anaconda3  (writable)
         channel URLs : https://repo.anaconda.com/pkgs/main/osx-64
                        https://repo.anaconda.com/pkgs/main/noarch
                        https://repo.anaconda.com/pkgs/free/osx-64
                        https://repo.anaconda.com/pkgs/free/noarch
                        https://repo.anaconda.com/pkgs/r/osx-64
                        https://repo.anaconda.com/pkgs/r/noarch
                        https://repo.anaconda.com/pkgs/pro/osx-64
                        https://repo.anaconda.com/pkgs/pro/noarch
        package cache : /anaconda3/pkgs
                        /Users/alex/.conda/pkgs
     envs directories : /anaconda3/envs
                        /Users/alex/.conda/envs
             platform : osx-64
           user-agent : conda/4.5.12 requests/2.19.1 CPython/3.6.5 Darwin/18.2.0 OSX/10.14.2
              UID:GID : 501:20
           netrc file : None
         offline mode : False
  
  # conda environments:
  #
  base                     /anaconda3
  work_python36         *  /anaconda3/envs/work_python36
  
  sys.version: 3.6.5 |Anaconda, Inc.| (default, Apr 26 ...
  sys.prefix: /anaconda3
  sys.executable: /anaconda3/bin/python
  conda location: /anaconda3/lib/python3.6/site-packages/conda
  conda-build: /anaconda3/bin/conda-build
  conda-convert: /anaconda3/bin/conda-convert
  conda-develop: /anaconda3/bin/conda-develop
  conda-env: /anaconda3/bin/conda-env
  conda-index: /anaconda3/bin/conda-index
  conda-inspect: /anaconda3/bin/conda-inspect
  conda-metapackage: /anaconda3/bin/conda-metapackage
  conda-render: /anaconda3/bin/conda-render
  conda-server: /anaconda3/bin/conda-server
  conda-skeleton: /anaconda3/bin/conda-skeleton
  conda-verify: /anaconda3/bin/conda-verify
  user site dirs: 
  
  CIO_TEST: &lt;not set&gt;
  CONDA_BACKUP_HOST: x86_64-apple-darwin13.4.0
  CONDA_BUILD_SYSROOT: 
  /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk
  CONDA_DEFAULT_ENV: work_python36
  CONDA_EXE: /anaconda3/bin/conda
  CONDA_PREFIX: /anaconda3/envs/work_python36
  CONDA_PROMPT_MODIFIER: (work_python36) 
  CONDA_PYTHON_EXE: /anaconda3/bin/python
  CONDA_ROOT: /anaconda3
  CONDA_SHLVL: 1
  PATH: /anaconda3/bin:/anaconda3/envs/work_python36/bin:/anaconda3/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin
  PYTHONPATH: :~/anaconda3/envs/work_python36
  REQUESTS_CA_BUNDLE: &lt;not set&gt;
  SSL_CERT_FILE: &lt;not set&gt;
  WARNING: could not import _license.show_info
  # try:
  # $ conda install -n root _license
  </code></pre>