def get_env(self):
        """
        Return a copy of the `os.environ` object that sets up `PYTHONPATH` correctly, depending on the test suite it's
        invoked from. This is useful for invoking external programs from the test suite - e.g. distributed training.

        It always inserts `./src` first, then `./tests` or `./examples` depending on the test suite type and finally
        the preset `PYTHONPATH` if any (all full resolved paths).

        """
        env = os.environ.copy()
        paths = [self.src_dir_str]
        if "/examples" in self.test_file_dir_str:
            paths.append(self.examples_dir_str)
        else:
            paths.append(self.tests_dir_str)
        paths.append(env.get("PYTHONPATH", ""))

        env["PYTHONPATH"] = ":".join(paths)
        return env

        Return a copy of the `os.environ` object that sets up `PYTHONPATH` correctly, depending on the test suite it's
        invoked from. This is useful for invoking external programs from the test suite - e.g. distributed training.

        It always inserts `./src` first, then `./tests` or `./examples` depending on the test suite type and finally
        the preset `PYTHONPATH` if any (all full resolved paths).

        
dpkd/transformers/src/transformers/testing_utils.py