  from django.db.models.fields.related import ManyToManyField
  from django.db.transaction import atomic
  from django.utils.log import getLogger
  from django.utils.six.moves import reduce
  from django.utils.six import callable
  
 
</s> remove     models = [Author, AuthorWithM2M, Book, BookWithSlug, BookWithM2M, Tag, TagIndexed, TagM2MTest, TagUniqueRename, UniqueTest]
 </s> add     models = [
        Author, AuthorWithM2M, Book, BookWithLongName, BookWithSlug,
        BookWithM2M, Tag, TagIndexed, TagM2MTest, TagUniqueRename, UniqueTest,
    ] </s> remove from .models import Author, AuthorWithM2M, Book, BookWithSlug, BookWithM2M, Tag, TagIndexed, TagM2MTest, TagUniqueRename, UniqueTest
 </s> add from .models import (Author, AuthorWithM2M, Book, BookWithLongName,
    BookWithSlug, BookWithM2M, Tag, TagIndexed, TagM2MTest, TagUniqueRename,
    UniqueTest) </s> remove             index_name = hashlib.md5(index_name).hexdigest()[:self.connection.features.max_index_name_length]
 </s> add             index_name = hashlib.md5(force_bytes(index_name)).hexdigest()[:self.connection.features.max_index_name_length]
from django.utils.encoding import force_bytes
  from django.db.models.fields.related import ManyToManyField
  from django.db.transaction import atomic
from django.utils.encoding import force_bytes
  from django.utils.log import getLogger
  from django.utils.six.moves import reduce
  from django.utils.six import callable
  
keep add keep keep keep keep
 Fixed #21497 -- Forced conversion to bytes for very long index names 
django/db/backends/schema.py