code: def testRegression(self):
      inputArray = readVector(join(filedir(), "flatness", "input.txt"))
      flatness = readVector(join(filedir(), "flatness", "output.txt"))[
          0
      ]
  
      self.assertAlmostEqual(Flatness()(inputArray), flatness, 1e-5)
  
file_path: essentia/test/src/unittests/stats/test_flatness.py
imports: from essentia_test import *
label_desc: Use image node_id 6 for calling the TestFlatness obj's underlying member method code with example usage: obj.testRegression() without return types