def get_readonly_fields(self, request, obj=None):
readonly_fields = super(EnterpriseCustomerUserAdmin, self).get_readonly_fields(request, obj=obj)<EOL>if obj:  <EOL><INDENT>return readonly_fields + tuple(get_all_field_names(self.model))<EOL><DEDENT>return readonly_fields<EOL>
Make all fields readonly when editing existing model.