code: def test_attribute_mode(self):
      self.tempfile()
      self.run_test(
          """
              def _attribute_mode(filename):
                  f = open(filename, 'a')
                  c = f.mode
                  f.close()
                  return c""",
          self.filename,
          _attribute_mode=[str],
      )
  
imports: from tempfile import mkstemp
  from pythran.tests import TestEnv
  import unittest
  from pythran.typing import List
label_desc: Use image node_id 32 for calling the TestFile obj's underlying member method code with example usage: obj.test_attribute_mode() without return types