From 4ad4500bc5527729f14eb3d2f86941a6aee715ad Mon Sep 17 00:00:00 2001
From: "Oriol (ZBook)" <oriol.abril.pla@gmail.com>
Date: Thu, 16 Dec 2021 01:08:02 +0200
Subject: [PATCH] sphinx maintenance

---
 examples/404.md       | 44 +++++++++++++++++++++++++++++++++++++++++++
 examples/conf.py      |  3 ++-
 requirements-docs.txt |  1 +
 3 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 examples/404.md

diff --git a/examples/404.md b/examples/404.md
new file mode 100644
index 000000000..25fa2fd3c
--- /dev/null
+++ b/examples/404.md
@@ -0,0 +1,44 @@
+---
+orphan: true
+---
+
+# Page not found
+
+**Sorry, we could not find this page**
+
+We are working on the next major release for PyMC,
+which will come with faster sampling, more flexible
+model building, multiple computational backends...
+
+::::{grid} 3
+:::{grid-item}
+![old banner](https://raw.githubusercontent.com/pymc-devs/pymc/v3/docs/logos/svg/PyMC3_banner.svg)
+:::
+:::{grid-item}
+:class: text-center
+{fas}`arrow-alt-circle-right;fa-5x`
+:::
+:::{grid-item}
+![new banner](https://raw.githubusercontent.com/pymc-devs/pymc/main/docs/logos/svg/PyMC_banner.svg)
+:::
+::::
+
+...and much better documentation too! However, to
+do so we have moved some files around and we have
+modified the base url in order to support multi version docs
+and better rendering and cross-referencing for notebooks.
+
+::::{grid} 3
+:::{grid-item}
+:::
+:::{grid-item}
+```{button-link} https://docs.pymc.io/projects/examples/en/latest/
+:color: primary
+:expand:
+
+Back to example gallery homepage
+```
+:::
+:::{grid-item}
+:::
+::::
diff --git a/examples/conf.py b/examples/conf.py
index 74950e233..9e85afecb 100644
--- a/examples/conf.py
+++ b/examples/conf.py
@@ -19,7 +19,8 @@
     "sphinxext.opengraph",
     "sphinx_copybutton",
     "sphinxcontrib.bibtex",
-    # "sphinx_codeautolink",
+    "sphinx_codeautolink",
+    "notfound.extension",
 ]
 
 # List of patterns, relative to source directory, that match files and
diff --git a/requirements-docs.txt b/requirements-docs.txt
index 73a72ccd8..68bd2c34f 100644
--- a/requirements-docs.txt
+++ b/requirements-docs.txt
@@ -7,3 +7,4 @@ sphinxcontrib-bibtex
 ablog
 sphinxext-opengraph
 sphinx-codeautolink
+sphinx-notfound-page