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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def decrypt_stream(mode, in_stream, out_stream, block_size = BLOCK_SIZE, padding = PADDING_DEFAULT):
    'Decrypts a stream of bytes from in_stream to out_stream using mode.'

    decrypter = Decrypter(mode, padding = padding)
    _feed_stream(decrypter, in_stream, out_stream, block_size)