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.