# Sphinx version: 1.8.5
# Python version: 3.7.4 (CPython)
# Docutils version: 0.14 
# Jinja2 version: 2.10.1
# Last messages:
#   Running Sphinx v1.8.5
#   connecting events for openstackdocstheme
#   making output directory...
#   Using openstackdocstheme Sphinx theme from /usr/lib/python3.7/site-packages/openstackdocstheme/theme
#   building [mo]: targets for 0 po files that are out of date
#   building [html]: targets for 17 source files that are out of date
#   updating environment:
#   17 added, 0 changed, 0 removed
#   reading sources... [  5%] cli/index
#   reading sources... [ 11%] cli/orchestration
# Loaded extensions:
#   sphinx.ext.mathjax (1.8.5) from /usr/lib/python3.7/site-packages/sphinx/ext/mathjax.py
#   alabaster (0.7.11) from /usr/lib/python3.7/site-packages/alabaster/__init__.py
#   sphinx.ext.autodoc (1.8.5) from /usr/lib/python3.7/site-packages/sphinx/ext/autodoc/__init__.py
#   openstackdocstheme (unknown version) from /usr/lib/python3.7/site-packages/openstackdocstheme/__init__.py
#   cliff.sphinxext (unknown version) from /usr/lib/python3.7/site-packages/cliff/sphinxext.py
Traceback (most recent call last):
  File "/usr/lib/python3.7/site-packages/sphinx/setup_command.py", line 193, in run
    app.build(force_all=self.all_files)
  File "/usr/lib/python3.7/site-packages/sphinx/application.py", line 341, in build
    self.builder.build_update()
  File "/usr/lib/python3.7/site-packages/sphinx/builders/__init__.py", line 347, in build_update
    len(to_build))
  File "/usr/lib/python3.7/site-packages/sphinx/builders/__init__.py", line 360, in build
    updated_docnames = set(self.read())
  File "/usr/lib/python3.7/site-packages/sphinx/builders/__init__.py", line 468, in read
    self._read_serial(docnames)
  File "/usr/lib/python3.7/site-packages/sphinx/builders/__init__.py", line 490, in _read_serial
    self.read_doc(docname)
  File "/usr/lib/python3.7/site-packages/sphinx/builders/__init__.py", line 534, in read_doc
    doctree = read_doc(self.app, self.env, self.env.doc2path(docname))
  File "/usr/lib/python3.7/site-packages/sphinx/io.py", line 318, in read_doc
    pub.publish()
  File "/usr/lib/python3.7/site-packages/docutils/core.py", line 217, in publish
    self.settings)
  File "/usr/lib/python3.7/site-packages/docutils/readers/__init__.py", line 72, in read
    self.parse()
  File "/usr/lib/python3.7/site-packages/docutils/readers/__init__.py", line 78, in parse
    self.parser.parse(self.input, document)
  File "/usr/lib/python3.7/site-packages/sphinx/parsers.py", line 88, in parse
    self.statemachine.run(inputstring, document, inliner=self.inliner)
  File "/usr/lib/python3.7/site-packages/docutils/parsers/rst/states.py", line 171, in run
    input_source=document['source'])
  File "/usr/lib/python3.7/site-packages/docutils/statemachine.py", line 239, in run
    context, state, transitions)
  File "/usr/lib/python3.7/site-packages/docutils/statemachine.py", line 460, in check_line
    return method(match, context, next_state)
  File "/usr/lib/python3.7/site-packages/docutils/parsers/rst/states.py", line 2988, in text
    self.section(title.lstrip(), source, style, lineno + 1, messages)
  File "/usr/lib/python3.7/site-packages/docutils/parsers/rst/states.py", line 327, in section
    self.new_subsection(title, lineno, messages)
  File "/usr/lib/python3.7/site-packages/docutils/parsers/rst/states.py", line 395, in new_subsection
    node=section_node, match_titles=True)
  File "/usr/lib/python3.7/site-packages/docutils/parsers/rst/states.py", line 282, in nested_parse
    node=node, match_titles=match_titles)
  File "/usr/lib/python3.7/site-packages/docutils/parsers/rst/states.py", line 196, in run
    results = StateMachineWS.run(self, input_lines, input_offset)
  File "/usr/lib/python3.7/site-packages/docutils/statemachine.py", line 239, in run
    context, state, transitions)
  File "/usr/lib/python3.7/site-packages/docutils/statemachine.py", line 460, in check_line
    return method(match, context, next_state)
  File "/usr/lib/python3.7/site-packages/docutils/parsers/rst/states.py", line 2326, in explicit_markup
    nodelist, blank_finish = self.explicit_construct(match)
  File "/usr/lib/python3.7/site-packages/docutils/parsers/rst/states.py", line 2338, in explicit_construct
    return method(self, expmatch)
  File "/usr/lib/python3.7/site-packages/docutils/parsers/rst/states.py", line 2081, in directive
    directive_class, match, type_name, option_presets)
  File "/usr/lib/python3.7/site-packages/docutils/parsers/rst/states.py", line 2130, in run_directive
    result = directive_instance.run()
  File "/usr/lib/python3.7/site-packages/cliff/sphinxext.py", line 363, in run
    app = self._load_app()
  File "/usr/lib/python3.7/site-packages/cliff/sphinxext.py", line 245, in _load_app
    if not issubclass(cliff_app_class, app.App):
TypeError: issubclass() arg 1 must be a class