161     >>> s = bytestr(b'foo')

   161     >>> s = bytestr(b'foo')

   162     >>> assert s is bytestr(s)

   162     >>> assert s is bytestr(s)

   163 

   163 

   164     __bytes__() should be called if provided:

   164     __bytes__() should be called if provided:

   165 

   165 

   167     ...     def __bytes__(self):

   167     ...     def __bytes__(self):

   168     ...         return b'bytes'

   168     ...         return b'bytes'

   169     >>> bytestr(bytesable())

   169     >>> bytestr(bytesable())

   170     'bytes'

   170     'bytes'

   171 

   171