According to [os.getenv()](https://docs.python.org/3/library/os.html#os.getenv) documentation, a string is returned, no need to wrap the result in `str()` again.
According to [os.getenv()](https://docs.python.org/3/library/os.html#os.getenv) documentation, a string is returned, no need to wrap the result in `str()` again.