>>> import io
>>> class F(io.FileIO): pass
... 
>>> f = F('/dev/null', 'r')
>>> f
<_io.FileIO name='/dev/null' mode='rb'>
>>> class B(io.BufferedReader): pass
... 
>>> b = B(f)
>>> b
<B name='/dev/null'>
>>> class T(io.TextIOBufferedReader): pass
io.TextIOBase(     io.TextIOWrapper(  
>>> class T(io.TextIOWrapper): pass
... 
>>> t = T(b)
>>> t
<_io.TextIOWrapper name='/dev/null' encoding='UTF-8'>

Expected results are "<__main__.F name='/dev/null' mode='rb'>", "<__main__.B name='/dev/null'>" and "<__main__.T name='/dev/null' encoding='UTF-8'>". Usually reprs of subclass instances substitute actual module and class names.