how to set active for base hmtml files in django code example

Example: bootstrap Navbar active in django

# navbar_demo/pages/views.py... 

'''We will pass a unique variable for each page whose value will be 'active' to make 
a page active in navbar when it call.'''

def index(request):    
  context = {"home_page": "active"} # new info here    
  return render(request, 'pages/index.html', context)

def about(request):    
  context = {"about_page": "active"} # new info here    
  return render(request, 'pages/about.html', context)

def contact(request):    
  context = {"contact_page": "active"} # new info here    
  return render(request, 'pages/contact.html', context)

# In html file #
 
'''  
<ul class="navbar-nav">
  <li class="nav-item {{ home_page }}">
      <a class="nav-link" href="{% url 'index' %}">Home</a>
   </li>
   <li class="nav-item {{ about_page }}">
      <a class="nav-link" href="{% url 'about' %}">About</a>
    </li>
   <li class="nav-item {{ contact_page }}">
       <a class="nav-link" href="{% url 'contact' %}">Contact</a>
    </li>
 </ul>
'''