The linked code at https://github.com/vadmium/python-iview/commit/68b0559 seems strange to me:

    try:
        text.encode(encoding, textio.errors or "strict")
    except UnicodeEncodeError:
        text = text.encode(encoding, errors).decode(encoding)
    return text

is the same as:

    return text.encode(encoding, errors).decode(encoding)

because when there are no unencodable characters in text, the error handler will never be invoked.