code: def clear_target():
      if not os.path.isfile(TARGET_FILE):
          return
      os.remove(TARGET_FILE)
  
imports: from __future__ import absolute_import, print_function
  import os
  import tensorflow
  from niftynet.engine.application_driver import ApplicationDriver
  from niftynet.utilities.util_common import ParserNamespace
  from tests.niftynet_testcase import NiftyNetTestCase
label_desc: Use image node_id 4 for calling a global function with example usage: clear_target() without return types