old_contents: """
  Admin views for the database mutex app.
  """
  
  from django.contrib import admin
  
  from .models import DbMutexLock
  
  
  class DbMutexLockAdmin(admin.ModelAdmin):
      """
      ``DbMutexLock`` admin form.
      """
  
      list_display = ('mutex_name',
                      'creation_date',
                      'expired')
  
      list_filter = ('creation_date',)
  
      search_fields = ('mutex_name',)
  
  
  admin.site.register(DbMutexLock, DbMutexLockAdmin)
  
new_contents: """
  Admin views for the database mutex app.
  """
  
  from django.contrib import admin
  
  from .models import DbMutexLock
  
  
  class DbMutexLockAdmin(admin.ModelAdmin):
      """
      ``DbMutexLock`` admin form.
      """
  
      list_display = ('mutex_name',
                      'creation_date',
                      'expired')
  
      list_filter = ('creation_date', )
  
      search_fields = ('mutex_name', )
  
  
  admin.site.register(DbMutexLock, DbMutexLockAdmin)
  
subject: Fix PEP8