ingests and deparses a given code block 'co'

def code_deparse_align(co, out=sys.stderr, version=None, is_pypy=None,
                       debug_opts=DEFAULT_DEBUG_OPTS,
                       code_objects={}, compile_mode='exec'):
    """
    ingests and deparses a given code block 'co'
    """

    assert iscode(co)

    if version is None:
        version = float(sys.version[0:3])
    if is_pypy is None:
        is_pypy = IS_PYPY


    # store final output stream for case of error
    scanner = get_scanner(version, is_pypy=is_pypy)

    tokens, customize = scanner.ingest(co, code_objects=code_objects)
    show_asm = debug_opts.get('asm', None)
    maybe_show_asm(show_asm, tokens)

    debug_parser = dict(PARSER_DEFAULT_DEBUG)
    show_grammar = debug_opts.get('grammar', None)
    show_grammar = debug_opts.get('grammar', None)
    if show_grammar:
        debug_parser['reduce'] = show_grammar
        debug_parser['errorstack'] = True

    #  Build a parse tree from tokenized and massaged disassembly.
    show_ast = debug_opts.get('ast', None)
    deparsed = AligningWalker(version, scanner, out, showast=show_ast,
                            debug_parser=debug_parser, compile_mode=compile_mode,
                            is_pypy = is_pypy)

    isTopLevel = co.co_name == '<module>'
    deparsed.ast = deparsed.build_ast(tokens, customize, isTopLevel=isTopLevel)

    assert deparsed.ast == 'stmts', 'Should have parsed grammar start'

    del tokens # save memory

    deparsed.mod_globs = find_globals(deparsed.ast, set())

    # convert leading '__doc__ = "..." into doc string
    try:
        if deparsed.ast[0][0] == ASSIGN_DOC_STRING(co.co_consts[0]):
            deparsed.print_docstring('', co.co_consts[0])
            del deparsed.ast[0]
        if deparsed.ast[-1] == RETURN_NONE:
            deparsed.ast.pop() # remove last node
            # todo: if empty, add 'pass'
    except:
        pass

    # What we've been waiting for: Generate Python source from the parse tree!
    deparsed.gen_source(deparsed.ast, co.co_name, customize)

    for g in sorted(deparsed.mod_globs):
        deparsed.write('# global %s ## Warning: Unused global\n' % g)

    if deparsed.ERROR:
        raise SourceWalkerError("Deparsing stopped due to parse error")
    return deparsed