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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_task_target():
 """Get the default target for a pipeline task. Current version id format is: user_defined_version.minor_version_number Current module id is just the module's name. It could be "default" Returns: A complete target name is of format version.module. If module is the default module, just version. None if target can not be determined. """

  # Break circular dependency.
  # pylint: disable=g-import-not-at-top
  import pipeline
  if pipeline._TEST_MODE:
    return None

  # Further protect against test cases that doesn't set env vars
  # propertly.
  if ("CURRENT_VERSION_ID" not in os.environ or
      "CURRENT_MODULE_ID" not in os.environ):
    logging.warning("Running Pipeline in non TEST_MODE but important "
                    "env vars are not set.")
    return None

  version = os.environ["CURRENT_VERSION_ID"].split(".")[0]
  module = os.environ["CURRENT_MODULE_ID"]
  return "%s.%s" % (version, module)