python - Calling a class method from another class causes metaclass conflict -


i have python web app , want define general class or function processing web pages , call more specific class specific page instances.

error:

metaclass conflict: metaclass of derived class must (non-strict) subclass of metaclasses of bases

i have checked stackoverflow questions & answers error message , did not understand explanations given (and found article metaclasses didn't understand - oop not thing). looked @ stackoverflow questions & answers calling class method class (and didn't understand them either).

code:

import webapp2 datetime import datetime, timedelta  google.appengine.ext import ndb google.appengine.api import users  import admin_templates import authenticate  class mypage(webapp2.requesthandler):     def get(pageinstance):         pageinstance.outputhtml()      def outputhtml(pageinstance,pagetitle,pagecontent):         adminlink = authenticate.get_adminlink()         authmessage = authenticate.get_authmessage()         adminnav = authenticate.get_adminnav()         pageinstance.response.headers['content-type'] = 'text/html'         html = admin_templates.base         html = html.replace('#title#', pagetitle)         html = html.replace('#authmessage#', authmessage)         html = html.replace('#adminlink#', adminlink)         html = html.replace('#adminnav#', adminnav)         html = html.replace('#content#', pagecontent)         pageinstance.response.out.write(html)         pageinstance.response.out.write(admin_templates.footer)  class auditorspage(webapp2.requesthandler, mypage.outputhtml):     def get(self):         self.output_auditors()      def output_auditors(self):         self.outputhtml(admin_templates.auditors_title, admin_templates.auditors_content)

how call outputhtml method in mypage class auditorspage class without getting metaclass error?

the error comes fact subclassing class method in general class, can't done. actually, code wrong, , there @ least 2 ways can fix it:

1) inherit mypage instead: in case, won't work , bring mro error because methods not part of instance of class, not linked object using self first parameter.

this fix code in case:

from google.appengine.ext import ndb google.appengine.api import users  import admin_templates import authenticate  class mypage(webapp2.requesthandler):     def get(self, pageinstance):         pageinstance.outputhtml()      def outputhtml(self, pageinstance,pagetitle,pagecontent):         adminlink = authenticate.get_adminlink()         authmessage = authenticate.get_authmessage()         adminnav = authenticate.get_adminnav()         pageinstance.response.headers['content-type'] = 'text/html'         html = admin_templates.base         html = html.replace('#title#', pagetitle)         html = html.replace('#authmessage#', authmessage)         html = html.replace('#adminlink#', adminlink)         html = html.replace('#adminnav#', adminnav)         html = html.replace('#content#', pagecontent)         pageinstance.response.out.write(html)         pageinstance.response.out.write(admin_templates.footer)  class auditorspage(mypage):     def get(self):         self.output_auditors()

2) 2 methods in mypage class normal methods no class, , call them directly class. actually, need create outputhtml() method, , call directly (without self.) method in requesthandler subclass.


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