old_contents: from Crypto.PublicKey import RSA
  
  from django.conf import settings
  from django.core.management.base import BaseCommand
  
  
  class Command(BaseCommand):
      help = 'Randomly generate a new RSA key for the OpenID server'
  
      def handle(self, *args, **options):
          try:
              key = RSA.generate(1024)
              file_path = settings.BASE_DIR + '/OIDC_RSA_KEY.pem'
              with open(file_path, 'w') as f:
                  f.write(key.exportKey('PEM'))
              self.stdout.write('RSA key successfully created at: ' + file_path)
          except Exception as e:
              self.stdout.write('Something goes wrong: {0}'.format(e))
  
new_contents: from Crypto.PublicKey import RSA
  
  from django.conf import settings
  from django.core.management.base import BaseCommand
  
  
  class Command(BaseCommand):
      help = 'Randomly generate a new RSA key for the OpenID server'
  
      def handle(self, *args, **options):
          try:
              key = RSA.generate(1024)
              file_path = settings.BASE_DIR + '/OIDC_RSA_KEY.pem'
              with open(file_path, 'wb') as f:
                  f.write(key.exportKey('PEM'))
              self.stdout.write('RSA key successfully created at: ' + file_path)
          except Exception as e:
              self.stdout.write('Something goes wrong: {0}'.format(e))
  
subject: Append binary file mode to write RSA exported key needed by Python 3