Cannot query "Python Tutorials Teaser": Must be "Subject" instance - python-3.x

Question

I am creating E-Learning website and I want to show "Course Content or Lession" as a playlist which is related to subject. Like that image
but I am getting error Cannot query "Python Tutorials Teaser": Must be "Subject" instance. Python Tutorials Teaser is title of the lession.
view.py
def allsubject(request):
subj = Subject.objects.all()
context = {'subj': subj}
return render(request, 'allsubject.html', context)
def pvideos(request, slug):
vds = Videos.objects.filter(slug=slug).first()
coursecontent = Videos.objects.filter(subject=vds)
context = {'vds':vds, 'coursecontent':coursecontent}
return render(request, 'pvideos.html', context)
models.py
class Videos(models.Model):
sno = models.AutoField(primary_key=True)
title = models.CharField(max_length=500)
cont = models.TextField()
vurl = models.URLField(max_length=200)
subject = models.ForeignKey(Subject, on_delete=models.CASCADE, related_name='videos')
position = models.PositiveSmallIntegerField(verbose_name="videono.")
slug = models.CharField(max_length=130)
timeStamp = models.DateTimeField(default=now)
def __str__(self):
return self.title
pvideo.html
{% extends 'base.html' %}
{% block title %}Free Video Course {% endblock title %}
{% block body %}
<div class="container">
<div class="embed-responsive embed-responsive-21by9">
<iframe class="embed-responsive-item" src="{{vds.vurl}}" allowfullscreen></iframe>
</div>
<ul class="nav nav-tabs" id="myTab" role="tablist">
<li class="nav-item">
<a class="nav-link active font-weight-bold" id="home-tab" data-toggle="tab" href="#overview" role="tab"
aria-controls="home" aria-selected="true">Overview</a>
</li>
<li class="nav-item">
<a class="nav-link font-weight-bold" id="profile-tab" data-toggle="tab" href="#coursecontent" role="tab"
aria-controls="profile" aria-selected="false">Course Content</a>
</li>
</ul>
<div class="tab-content" id="myTabContent">
<div class="tab-pane fade show active" id="overview" role="tabpanel" aria-labelledby="home-tab">
<h2>{{vds.title}}</h2>
<p>{{vds.cont|safe}}</p>
</div>
<div class="tab-pane fade" id="coursecontent" role="tabpanel" aria-labelledby="profile-tab">
{% for c in coursecontent %}
{{c.title}}
{% endfor %}
</div>
</div>
</div>
{% endblock body %}
I think I made a mistake on views.py coursecontent = Videos.objects.filter(subject=vds). I want to show this playlist on that page where I show lessions. I hope you understand what I want. If anyone has any other idea besides this, so please help me.
I user click on course content then I show all lession related to subject

Answer 1

You are right, you have made a mistake in coursecontent = Videos.objects.filter(subject=vds)
Subject must either be the pk or an instance of subject but you're giving it another video instance. What you want is
coursecontent = Videos.objects.filter(subject=vds.subject).exclude(sno=vds.sno)
.filter(subject=vds.subject) will give you all videos with the same subject.
.exclude(sno=vds.sno) will exclude the current video from the query. This is useful if you want to show only the other videos... If you want to include all, just skip that part.
As a side note, you might want to improve your variable naming.
vds could be called video (it's singular)
vurl could be just url
cont could be content
Most of your model names should be singular (coz each is a single instance).
An e-learning website is a nice initiative.