iotop -bo output can't be piped

Binary package hint: iotop

Attempting to pipe 'iotop -bo' or 'optop -bo 2>&1' to anything produced no output until after hitting 'ctrl-c' at which point produced the following:
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^Cclose failed in file object destructor:
Error in sys.excepthook:

Original exception was:
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iotop -b had no problems as far as I could tell

The easiest and most revealing way of producing this error was with 'iotop -bo | cat', but same error with sed and tee.

Using iotop version 0.2-3 (jaunty) and Ubuntu 9.04

I had expected it to work like 'top -bi | foo'