Index: slepc4py/docs/source/Makefile
===================================================================
--- slepc4py.orig/docs/source/Makefile	2021-04-24 00:48:05.232506385 +0200
+++ slepc4py/docs/source/Makefile	2021-04-24 00:48:05.224506974 +0200
@@ -3,7 +3,7 @@
 
 # You can set these variables from the command line.
 SPHINXOPTS    =
-SPHINXBUILD   = python -msphinx
+SPHINXBUILD   = python3 -msphinx
 SPHINXPROJ    = petsc4py
 SOURCEDIR     = .
 BUILDDIR      = _build