django matplotlib response as png

#matplot/views

from django.http import  HttpResponse
import matplotlib.pyplot as plt
import numpy as np
import io

def index(request):
    return HttpResponse('<h1>matplotlib app homepage</h1>')

def plot(request):
    # Data for plotting
    t = np.arange(0.0, 2.0, 0.01)
    s = 1 + np.sin(2 * np.pi * t)

    fig, ax = plt.subplots()
    ax.plot(t, s)
    ax.set(xlabel='time (s)', ylabel='voltage (mV)',
           title='About as simple as it gets, folks')
    ax.grid()

    buf = io.BytesIO()
    plt.savefig(buf, format='png')
    plt.close(fig)

    response = HttpResponse(buf.getvalue(), content_type='image/png')
    return response

--------------------------------
#matplot/urls

from django.urls import path
from . import views

urlpatterns = [
    path('', views.index, name='index'),
    path('chart/', views.plot, name='chart')
]

------------------------------
#django_matplotlib/urls

from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('matplot/', include('matplot.urls')),
]

reference:
https://stackoverflow.com/questions/49542459/error-in-django-when-using-matplotlib-examples
https://stackoverflow.com/questions/40534715/how-to-embed-matplotlib-graph-in-django-webpage