Test case for backend not defined; remove unreachable code Verify that error is raised in configuration.py if backend is not defined in config.ini. Remove unreachable code from instance.py that detects that backend is not defined. It hasn't been reachable since version 1.6.1 because the configuration.py module made the backend option mandatory. Hence configuration.py raises the error and never passes control back to the unreachable code.

try:
    from html import escape as html_escape_  # python 3

    def html_escape(str, quote=False):
        # html_escape under python 3 sets quote to true by default
        # make it python 2 compatible
        return html_escape_(str, quote=quote)
except ImportError:
    # python 2 fallback
    from cgi import escape as html_escape  # noqa: F401