                  if hasattr(self.stdin, 'isatty') and not self.stdin.isatty():
                      raise NotRunningInTTYException("Not running in a TTY")
  
                  # Get a username
                  verbose_field_name = self.username_field.verbose_name
                  while username is None:
                      input_msg = capfirst(verbose_field_name)
                      if default_username:
                          input_msg += " (leave blank to use '%s')" % default_username
                      username_rel = self.username_field.remote_field
 
</s>
                  if hasattr(self.stdin, 'isatty') and not self.stdin.isatty():
                      raise NotRunningInTTYException("Not running in a TTY")
  
                  # Get a username

                  while username is None:
                      input_msg = capfirst(verbose_field_name)
                      if default_username:
                          input_msg += " (leave blank to use '%s')" % default_username
                      username_rel = self.username_field.remote_field
keep keep keep keep replace keep keep keep keep keep
 Fixed #28591 -- Added an error message for createsuperuser --username= (blank).
django/contrib/auth/management/commands/createsuperuser.py