code: def test_flush(self):
      self.tempfile()
      # Don't know how to check properly, just checking fct call.
      self.run_test(
          """
              def _flush(filename):
                  f = open(filename, 'a')
                  f.flush()
                  f.close()""",
          self.filename,
          _flush=[str],
      )
  
imports: from tempfile import mkstemp
  from pythran.tests import TestEnv
  import unittest
  from pythran.typing import List
label_desc: Use image node_id 27 for calling the TestFile obj's underlying member method code with example usage: obj.test_flush() without return types