code: def test_attr_filter(self, env):
      env = SandboxedEnvironment()
      tmpl = env.from_string('{{ cls|attr("__subclasses__")() }}')
      pytest.raises(SecurityError, tmpl.render, cls=int)
  
imports: import pytest
  from jinja2 import Environment
  from jinja2 import escape
  from jinja2 import Markup
  from jinja2._compat import text_type
  from jinja2.exceptions import SecurityError
  from jinja2.exceptions import TemplateRuntimeError
  from jinja2.exceptions import TemplateSyntaxError
  from jinja2.nodes import EvalContext
  from jinja2.sandbox import ImmutableSandboxedEnvironment
  from jinja2.sandbox import SandboxedEnvironment
  from jinja2.sandbox import unsafe
label_desc: Use image node_id 6 for calling the TestSandbox obj's underlying member method code with example usage: obj.test_attr_filter(env) without return types