How to implement a custom error code for use with Flask

gistfile1.py

from werkzeug.exceptions import HTTPException


class FailedDependency(HTTPException):
    code = 424
    description = "The request failed due to failure of a previous request."
    name = "Failed Dependency"

    def get_response(self, environment):
        resp = super(FailedDependency, self).get_response(environment)
        resp.status = "%s %s" % (self.code, self.name.upper())
        return resp


# using it
import requests

def fetch_tags():
    url = "https://api.github.com/repos/mozilla/socorro/git/refs/tags"
    response = requests.get(url)
    if response.status_code == 200:
        return response.json()
    raise FailedDependency