bug: Allow UsageError exception to use more specific error code UsageError exception returned 400 error code but should return 405 when generated for a bad http method. Modified error handler to use 400 error code if self.response_code was less then 400. This should reproduce the standard error of 400 if one was not specified and preserve any other explicitly set response code. Also enhanced a test case to verify the 405 is returned.

try:
    from html import escape as html_escape_  # python 3

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