title: "conda export" can not export packages that is installed through pip
body: <p>I want to use package <code>untangle</code>, unfortunately, it can not be installed through conda, I have to install it using pip. And when I use <code>conda export</code> to export the requirement file, I find that the requirement file doesn't include <code>untangle</code>, is there any way to also include it in conda requirement file and export the conda virtual enviroment ? Thanks</p>