Use switch_backend instead, see...

Use switch_backend instead, see https://github.com/matplotlib/matplotlib/issues/3466/#issuecomment-270603717

bob/bio/base/script/evaluate.py

@@ -11,7 +11,7 @@ from __future__ import print_function
 # matplotlib stuff
 import matplotlib
 from matplotlib import pyplot
-pyplot.ioff() # turn off interactive mode -- no figure window will be shown
+pyplot.switch_backend('agg')  # switch to non-X backend
 from matplotlib.backends.backend_pdf import PdfPages
 
 # import bob.measure after matplotlib, so that it cannot define the backend

[Tiago de Freitas Pereira]

Awesome, thanks @mguenther