title: Python NoReverseMatch for Argument
body: <p>I am new to Python Django and I am struggling with URL patterns,My creating websites which has three Html pages and their three respective views,I am attchaing the images of My code and project structure Please help me to find the solution:
  Project Structure:-
  <a href="https://i.stack.imgur.com/TZQME.png" rel="nofollow noreferrer">enter image description here</a></p>
  
  <p>So idea is when i click on index.html the page gets redirect to detail.html with image id like 'music/id' now i want to redirect to other html page on image click in detail.html to picturedetail.html with 'song_title' attribute</p>
  
  <p>Code:-</p>
  
  <ol>
  <li><p>Models.py:-</p>
  
  <pre><code>from django.db import models
  
  
  
  class Album(models.Model):
    art_type=models.CharField(max_length=255)
    album_title=models.CharField(max_length=255)
    art_method=models.CharField(max_length=255)
    album_logo=models.FileField()
  
  def __str__(self):
      return self.album_title;
  
  
  class Picture(models.Model):
    album=models.ForeignKey(Album,on_delete=models.CASCADE)
    file_type=models.FileField()
    song_title=models.CharField(max_length=245)
  </code></pre></li>
  <li><p>detail.html:-</p>
  
  <pre><code>  {% extends 'music/base.html'  %}
    {% block title %}Album Details{% endblock %}
    {% block body %}
    &lt;ul&gt;
       {% for picture in album.picture_set.all %}
        &lt;div class="col-sm-4 col-lg-2"&gt;
             &lt;div class="thumbnail"&gt;
                &lt;a href="{% url 'music:picturedetail' picture.song_title %}"&gt;
                 &lt;img src="{{ picture.file_type.url }}" class="img-responsive"&gt;
                          &lt;/a&gt;
                          &lt;div class="caption"&gt;
                            &lt;h6&gt;{{picture.song_title}}&lt;/h6&gt;
                          &lt;/div&gt;
                  &lt;/div&gt;
  
          &lt;/div&gt;
  
       {% endfor %}
    &lt;/ul&gt;
  </code></pre>
  
  <p>{% endblock %}</p></li>
  <li><p>urls.py:-</p>
  
  <p>from django.conf.urls import url
      from . import views</p>
  
  <pre><code>app_name='music';
  urlpatterns = [
  
      url(r'^$',views.IndexView.as_view(),name='index'),
  
      # /music/id/
      url(r'^(?P&lt;pk&gt;[0-9]+)$',views.DetailView.as_view(),name='detail'),
      #for PictureDetail view
      url(r'^(?P&lt;pk&gt;[0-9]+)/(?P&lt;song_title&gt;[A-Za-z]+)', views.PicturedetailView.as_view(), name='picturedetail'),
  
  ]
  </code></pre></li>
  </ol>
  
  <p>4.view.py:-</p>
  
  <pre><code>from django.views import generic
  from .models import Album
  from .models import Picture
  
  
  
  class IndexView(generic.ListView):
      template_name = 'music/index.html'
      context_object_name = 'all_albums'
      def get_queryset(self):
          return Album.objects.all()
  
  class DetailView(generic.DetailView):
       model=Album
       template_name = 'music/detail.html '
  
  
  class PicturedetailView(generic.DetailView):
      model =Picture
      template_name = 'music/picturedetail.html'
  </code></pre>
  
  <p>The Error i am getting is:-</p>
  
  <pre><code>  NoReverseMatch at /music/1
  Reverse for 'picturedetail' with arguments '('River',)' not found. 1 pattern(s) tried: ['music/(?P&lt;pk&gt;[0-9]+)/(?P&lt;song_title&gt;[A-Za-z]+)']
  Request Method: GET
  Request URL:    http://127.0.0.1:8000/music/1
  Django Version: 2.0.6
  Exception Type: NoReverseMatch
  Exception Value:    
  Reverse for 'picturedetail' with arguments '('River',)' not found. 1 pattern(s) tried: ['music/(?P&lt;pk&gt;[0-9]+)/(?P&lt;song_title&gt;[A-Za-z]+)']
  Exception Location: C:\Users\dell\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django-2.0.6-py3.6.egg\django\urls\resolvers.py in _reverse_with_prefix, line 636
  Python Executable:  C:\Users\dell\AppData\Local\Programs\Python\Python36-32\python.exe
  Python Version: 3.6.1
  Python Path:    
  ['D:\\Django\\website',
   'C:\\Users\\dell\\AppData\\Local\\Programs\\Python\\Python36-32\\python36.zip',
   'C:\\Users\\dell\\AppData\\Local\\Programs\\Python\\Python36-32\\DLLs',
   'C:\\Users\\dell\\AppData\\Local\\Programs\\Python\\Python36-32\\lib',
   'C:\\Users\\dell\\AppData\\Local\\Programs\\Python\\Python36-32',
   'C:\\Users\\dell\\AppData\\Local\\Programs\\Python\\Python36-32\\lib\\site-packages',
   'C:\\Users\\dell\\AppData\\Local\\Programs\\Python\\Python36-32\\lib\\site-packages\\django-2.0.6-py3.6.egg',
   'C:\\Users\\dell\\AppData\\Local\\Programs\\Python\\Python36-32\\lib\\site-packages\\pytz-2018.4-py3.6.egg']
  Server time:    Fri, 6 Jul 2018 03:00:51 +0000
  </code></pre>