How to use the pysnooper.utils.WritableStream function in PySnooper

except UnicodeEncodeError:
                 # God damn Python 2
                stderr.write(utils.shitcode(s))
        truncate = None
    elif isinstance(output, (pycompat.PathLike, str)):
        def write(s):
            with open(six.text_type(output), 'a') as output_file:
                output_file.write(s)
        def truncate():
            with open(six.text_type(output), 'w') as output_file:
                pass
    elif callable(output):
        write = output
        truncate = None
    else:
        assert isinstance(output, utils.WritableStream)
        def write(s):
            output.write(s)
        truncate = None

    return (write, truncate)