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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_key_file_path():
 """Return the key file path."""

        if os.getenv(USER_HOME) is not None and os.access(os.getenv(USER_HOME),
                                                          os.W_OK):
            return os.path.join(os.getenv(USER_HOME), KEY_FILE_NAME)

        return os.path.join(os.getcwd(), KEY_FILE_NAME)