django models relations getting count of given tasks

Trying to fetch a function from a table that is supposed to be there, but cannot get the value. Trying to get the amount of task that is completed.

models.py

class Task(models.Model):
    title           = models.CharField(max_length=55, null=True, blank=True)
    slug            = models.SlugField(max_length=500, unique=True, blank=True)
    task_completed  = models.BooleanField(default=False)
    description     = models.TextField(default="Task description")
    start_date      = models.DateTimeField()
    due_date        = models.DateTimeField()

    checklist       = models.ManyToManyField(Checklist, blank=True)

    def save(self, *args, **kwargs):
        if not self.slug:
            self.slug = slugify(self.title)
        super(Task, self).save(*args, **kwargs)

    def get_url(self):
        return reverse('checklists', kwargs={
            'slug':self.slug
        })

    def __str__(self):
        return self.title

    @property
    def num_task_completed(self):
        return self.task_completed.count()

class Project(models.Model):
    project_manager = models.ForeignKey(Profile, on_delete=CASCADE)

    title           = models.CharField(max_length=55, null=True, blank=True)
    developers      = models.ManyToManyField(Profile, related_name='projects')
    slug            = models.SlugField(max_length=500, unique=True, blank=True)
    description     = models.TextField(default="Project description")
    date            = models.DateTimeField(auto_now_add=True)
    start_date      = models.DateTimeField()
    due_date        = models.DateTimeField()

    tasks           = models.ManyToManyField(Task, blank=True)
    teams           = models.ManyToManyField(Team, blank=True)
    
    def save(self, *args, **kwargs):
        if not self.slug:
            self.slug = slugify(self.title)
        super(Project, self).save(*args, **kwargs)

    def get_url(self):
        return reverse('project_detail', kwargs={
            'slug':self.slug
        })

    def __str__(self):
        return self.title

    @property
    def num_task(self):
        return self.tasks.count()

Then in the html is just loop through all projects

 {% for projects in projects.all %}
 <span class="text-small"> {{ projects.tasks.num_task_completed }} /{{ projects.num_task }}</span>

I manage to get the amount of tasks, but not the amount completed.

Solution 1:

Use self.tasks.filter(task_completed = True).count() to get the number of completed tasks in a project.