mpl_import_error

plasmapy.optional_deps.mpl_import_error = ImportError('\n matplotlib could not be found. Try either\n\n conda install matplotlib\n\n on Anaconda environments or\n\n pip install matplotlib\n\n in general. In case of trouble refer to\n\n https://matplotlib.org/users/installing.html\n\n (link active as of 2018.10.31 - please report dead links on GitHub!)')

Import error message for matplotlib.