old_contents: 
  # Imports #####################################################################
  
  from haystack import indexes
  
  from .models import Book
  
  
  # Classes #####################################################################
  
  class BookIndex(indexes.SearchIndex, indexes.Indexable):
      text = indexes.CharField(document=True, use_template=True)
      title = indexes.CharField(model_attr='title')
      subtitle = indexes.CharField(model_attr='subtitle')
      isbn = indexes.CharField(model_attr='isbn')
      author = indexes.CharField(model_attr='author')
      illustrator = indexes.CharField(model_attr='illustrator')
      editor = indexes.CharField(model_attr='editor')
      collection = indexes.CharField(model_attr='collection')
      keywords = indexes.CharField(model_attr='keywords')
      synopsis = indexes.CharField(model_attr='synopsis')
  
      def get_model(self):
          return Book
  
new_contents: 
  # Imports #####################################################################
  
  from haystack import indexes
  
  from .models import Book
  
  
  # Classes #####################################################################
  
  class BookIndex(indexes.SearchIndex, indexes.Indexable):
      text = indexes.CharField(document=True, use_template=True)
      title = indexes.CharField(model_attr='title')
      subtitle = indexes.CharField(model_attr='subtitle', blank=True)
      isbn = indexes.CharField(model_attr='isbn')
      author = indexes.CharField(model_attr='author')
      illustrator = indexes.CharField(model_attr='illustrator', blank=True)
      editor = indexes.CharField(model_attr='editor')
      collection = indexes.CharField(model_attr='collection', blank=True)
      keywords = indexes.CharField(model_attr='keywords', blank=True)
      synopsis = indexes.CharField(model_attr='synopsis')
  
      def get_model(self):
          return Book
  
subject: Allow some blank fields in Booki model from search