diff --git a/docs/conf.py b/docs/conf.py
index d81c66685..dd86a87a6 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,83 +1,79 @@
-# -*- coding: utf-8 -*-
-
-import os
-import sys
-
-import matplotlib
-from sphinx.ext.autodoc import between
-
-from oemof.solph import __version__
-
-
-matplotlib.use("agg")
-sys.path.append(os.path.join(os.path.dirname(__file__), "..", "examples"))
-
-
-def setup(app):
-    # Register a sphinx.ext.autodoc.between listener to ignore everything
-    # between lines that contain the word IGNORE
-    app.connect("autodoc-process-docstring", between("^SPDX.*$", exclude=True))
-    return app
-
-
-extensions = [
-    "sphinx.ext.autodoc",
-    "sphinx.ext.autosummary",
-    "sphinx.ext.coverage",
-    "sphinx.ext.doctest",
-    "sphinx.ext.extlinks",
-    "sphinx.ext.ifconfig",
-    "sphinx.ext.napoleon",
-    "sphinx.ext.todo",
-    "sphinx.ext.viewcode",
-    "sphinx_copybutton",
-    "sphinx_design",
-]
-source_suffix = ".rst"
-master_doc = "index"
-project = "oemof.solph"
-year = "2014-2023"
-author = "oemof-developer-group"
-copyright = "{0}, {1}".format(year, author)
-version = release = __version__
-
-pygments_style = "trac"
-templates_path = ["."]
-extlinks = {
-    "issue": ("https://github.com/oemof/oemof-solph/issues/%s", "#%s"),
-    "pr": ("https://github.com/oemof/oemof-solph/pull/%s", "PR #%s"),
-}
-# on_rtd is whether we are on readthedocs.org
-on_rtd = os.environ.get("READTHEDOCS", None) == "True"
-
-if not on_rtd:  # only set the theme if we're building docs locally
-    html_theme = "sphinx_rtd_theme"
-
-html_use_smartypants = True
-html_last_updated_fmt = "%b %d, %Y"
-html_split_index = False
-html_sidebars = {
-    "**": ["searchbox.html", "globaltoc.html", "sourcelink.html"],
-}
-html_short_title = "%s-%s" % (project, version)
-html_logo = "./_logo/logo_oemof_solph_COMPACT_bg.svg"
-
-napoleon_use_ivar = True
-napoleon_use_rtype = False
-napoleon_use_param = False
-nitpicky = False
-
-exclude_patterns = ["_build", "whatsnew/*"]
-
-linkcheck_ignore = [
-    r"https://requires.io/.*",
-    r"https://matrix.to/*",
-    r"https://forum.openmod-initiative.org/*",
-] + (
-    [
-        r"https://github.com/oemof/oemof-solph/issues/*",
-        r"https://github.com/oemof/oemof-solph/pull/*",
-    ]
-    if "TRAVIS" not in os.environ
-    else []
-)
+# -*- coding: utf-8 -*-
+
+import os
+import sys
+
+import matplotlib
+from sphinx.ext.autodoc import between
+
+from oemof.solph import __version__
+
+
+matplotlib.use("agg")
+sys.path.append(os.path.join(os.path.dirname(__file__), "..", "examples"))
+
+
+def setup(app):
+    # Register a sphinx.ext.autodoc.between listener to ignore everything
+    # between lines that contain the word IGNORE
+    app.connect("autodoc-process-docstring", between("^SPDX.*$", exclude=True))
+    return app
+
+
+extensions = [
+    "sphinx.ext.autodoc",
+    "sphinx.ext.autosummary",
+    "sphinx.ext.coverage",
+    "sphinx.ext.doctest",
+    "sphinx.ext.extlinks",
+    "sphinx.ext.ifconfig",
+    "sphinx.ext.napoleon",
+    "sphinx.ext.todo",
+    "sphinx.ext.viewcode",
+    "sphinx_copybutton",
+    "sphinx_design",
+]
+source_suffix = ".rst"
+master_doc = "index"
+project = "oemof.solph"
+year = "2014-2023"
+author = "oemof-developer-group"
+copyright = "{0}, {1}".format(year, author)
+version = release = __version__
+
+pygments_style = "trac"
+templates_path = ["."]
+extlinks = {
+    "issue": ("https://github.com/oemof/oemof-solph/issues/%s", "#%s"),
+    "pr": ("https://github.com/oemof/oemof-solph/pull/%s", "PR #%s"),
+}
+# on_rtd is whether we are on readthedocs.org
+on_rtd = os.environ.get("READTHEDOCS", None) == "True"
+
+if not on_rtd:  # only set the theme if we're building docs locally
+    html_theme = "sphinx_rtd_theme"
+
+html_use_smartypants = True
+html_last_updated_fmt = "%b %d, %Y"
+html_split_index = False
+html_sidebars = {
+    "**": ["searchbox.html", "globaltoc.html", "sourcelink.html"],
+}
+html_short_title = "%s-%s" % (project, version)
+html_logo = "./_logo/logo_oemof_solph_COMPACT_bg.svg"
+
+napoleon_use_ivar = True
+napoleon_use_rtype = False
+napoleon_use_param = False
+nitpicky = False
+
+exclude_patterns = ["_build", "whatsnew/*"]
+
+linkcheck_ignore = [
+    r"https://requires.io/.*",
+    r"https://matrix.to/*",
+    r"https://forum.openmod-initiative.org/*",
+    r"https://github.com/oemof/oemof-solph/issues/*",
+    r"https://github.com/oemof/oemof-solph/pull/*",
+    "https://www.sciencedirect.com/science/article/abs/pii/S036054421500331X",  # 403 in CI pipeline
+]