django - Type Error : 'authors' is an invalid key argument for this function -

i dont know why getting type error in piece of django app. below models.py code:

from django.db import models  # create models here. class publisher(models.model):     name = models.charfield(max_length=30)     address = models.charfield(max_length=50)     city = models.charfield(max_length=60)     state_province = models.charfield(max_length=30)     country = models.charfield(max_length=30)     website = models.urlfield()      def __str__(self):         return self.name  class author(models.model):     first_name = models.charfield(max_length=30)     last_name = models.charfield(max_length=40)     email = models.emailfield(verbose_name=' e-mail')      def __str__(self):         return "%s %s" %(self.first_name, self.last_name)  class book(models.model):     title = models.charfield(max_length=100)     authors = models.manytomanyfield(author)     publisher = models.foreignkey(publisher)     publication_date = models.datefield(blank=true, null=true)      def __str__(self):         return self.title 

i have created both author object , publisher object shell named (mak & mas) respectively.

>>> books.models import publisher, author, book >>> mak = author.objects.create(first_name = "kennedy") >>> mas = publisher.objects.create(name = "dreem inc") 

but when try populate book database table, type error:

>>> mybook = book(title="the prince", authors=mak, publisher=mas, publication_date = date(1989, 6, 30))  >>> type error : 'authors' invalid key argument function 

i can populate 'publisher' , "author" table.

please on this?

you can't assign manytomany field in model's constructor. can't set m2m field unsaved instance. have save instance first , assign m2m field:

mybook = author.objects.create(title="the prince", publisher=mas,                                publication_date=date(1989, 6, 30)) mybook.authors.add(mak) # or mybook.authors = [mak]