def setup(app):
-    app.add_stylesheet("css/ribbon.css")
+    app.add_css_file("css/ribbon.css")
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 [testenv:docs]
 basepython = python3
-deps = -r{toxinidir}/requirements-docs.txt
+deps =
+    -r{toxinidir}/requirements-docs.txt
+    -chttps://git.onap.org/doc/plain/etc/upper-constraints.os.txt
+    -chttps://git.onap.org/doc/plain/etc/upper-constraints.onap.txt
 commands =
     sphinx-build -b html -n -d {envtmpdir}/doctrees ./ {toxinidir}/_build/html
     echo "Generated docs available in {toxinidir}/_build/html"
 #deps = -r{toxinidir}/requirements-docs.txt
 commands = echo "Link Checking not enforced"
 #commands = sphinx-build -b linkcheck -d {envtmpdir}/doctrees ./ {toxinidir}/_build/linkcheck
-whitelist_externals = echo
+whitelist_externals = echo
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