code: def testPyMethods(self):
      env = MPI.INFO_ENV
      for key in self.KEYS:
          v = env.Get(key)
          del v
  
imports: from mpi4py import MPI
  import mpiunittest
  import sys
label_desc: Use image node_id 3 for calling the TestInfoEnv obj's underlying member method code with example usage: obj.testPyMethods() without return types