How to use the bytecode.instr.Label function in bytecode

def _flat(self):
        instructions = []
        labels = {}
        jumps = []

        offset = 0
        for index, instr in enumerate(self):
            if isinstance(instr, Label):
                instructions.append("label_instr%s" % index)
                labels[instr] = offset
            else:
                if isinstance(instr, Instr) and isinstance(instr.arg, Label):
                    target_label = instr.arg
                    instr = _bytecode.ConcreteInstr(instr.name, 0, lineno=instr.lineno)
                    jumps.append((target_label, instr))
                instructions.append(instr)
                offset += 1

        for target_label, instr in jumps:
            instr.arg = labels[target_label]

        return instructions

def from_bytecode(bytecode):
        # label => instruction index
        label_to_block_index = {}
        jumps = []
        block_starts = {}
        for index, instr in enumerate(bytecode):
            if isinstance(instr, Label):
                label_to_block_index[instr] = index
            else:
                if isinstance(instr, Instr) and isinstance(instr.arg, Label):
                    jumps.append((index, instr.arg))

        for target_index, target_label  in jumps:
            target_index = label_to_block_index[target_label]
            block_starts[target_index] = target_label

        bytecode_blocks = _bytecode.ControlFlowGraph()
        bytecode_blocks._copy_attr_from(bytecode)
        bytecode_blocks.argnames = list(bytecode.argnames)

        # copy instructions, convert labels to block labels
        block = bytecode_blocks[0]
        labels = {}

def _check_arg(self, name, opcode, arg):
        if opcode >= _opcode.HAVE_ARGUMENT:
            if arg is UNSET:
                raise ValueError("operation %s requires an argument" % name)
        else:
            if arg is not UNSET:
                raise ValueError("operation %s has no argument" % name)

        if self._has_jump(opcode):
            if not isinstance(arg, (Label, _bytecode.BasicBlock)):
                raise TypeError(
                    "operation %s argument type must be "
                    "Label or BasicBlock, got %s" % (name, type(arg).__name__)
                )

        elif opcode in _opcode.hasfree:
            if not isinstance(arg, (CellVar, FreeVar)):
                raise TypeError(
                    "operation %s argument must be CellVar "
                    "or FreeVar, got %s" % (name, type(arg).__name__)
                )

        elif opcode in _opcode.haslocal or opcode in _opcode.hasname:
            if not isinstance(arg, str):
                raise TypeError(
                    "operation %s argument must be a str, "

def _cmp_key(self, labels=None):
        arg = self._arg
        if self._opcode in _opcode.hasconst:
            arg = const_key(arg)
        elif isinstance(arg, Label) and labels is not None:
            arg = labels[arg]
        return (self._lineno, self._name, arg)

def concrete_instructions(self):
        ncells = len(self.bytecode.cellvars)
        lineno = self.bytecode.first_lineno

        for instr in self.bytecode:
            if isinstance(instr, Label):
                self.labels[instr] = len(self.instructions)
                continue

            if isinstance(instr, SetLineno):
                lineno = instr.lineno
                continue

            if isinstance(instr, ConcreteInstr):
                instr = instr.copy()
            else:
                assert isinstance(instr, Instr)

                if instr.lineno is not None:
                    lineno = instr.lineno

                arg = instr.arg

if instr.lineno is not None:
                cur_lineno = instr.lineno
            if lineno:
                fields.append(format_instr(instr))
                line = "".join(fields)
                line = format_line(offset, line)
            else:
                fields.append("% 3s    %s" % (offset, format_instr(instr)))
                line = "".join(fields)
            print(line)

            offset += instr.size
    elif isinstance(bytecode, Bytecode):
        labels = {}
        for index, instr in enumerate(bytecode):
            if isinstance(instr, Label):
                labels[instr] = "label_instr%s" % index

        for index, instr in enumerate(bytecode):
            if isinstance(instr, Label):
                label = labels[instr]
                line = "%s:" % label
                if index != 0:
                    print()
            else:
                if instr.lineno is not None:
                    cur_lineno = instr.lineno
                line = format_instr(instr, labels)
                line = indent + format_line(index, line)
            print(line)
        print()
    elif isinstance(bytecode, ControlFlowGraph):

continue
            target = instr.get_jump_target(offset)
            if target is not None:
                jump_targets.add(target)
            offset += instr.size

        # create labels
        jumps = []
        instructions = []
        labels = {}
        offset = 0
        ncells = len(self.cellvars)

        for lineno, instr in self._normalize_lineno():
            if offset in jump_targets:
                label = Label()
                labels[offset] = label
                instructions.append(label)

            jump_target = instr.get_jump_target(offset)
            size = instr.size

            arg = instr.arg
            # FIXME: better error reporting
            if instr.opcode in _opcode.hasconst:
                arg = self.consts[arg]
            elif instr.opcode in _opcode.haslocal:
                arg = self.varnames[arg]
            elif instr.opcode in _opcode.hasname:
                arg = self.names[arg]
            elif instr.opcode in _opcode.hasfree:
                if arg < ncells:

def to_bytecode(self):
        """Convert to Bytecode."""

        used_blocks = set()
        for block in self:
            target_block = block.get_jump()
            if target_block is not None:
                used_blocks.add(id(target_block))

        labels = {}
        jumps = []
        instructions = []

        for block in self:
            if id(block) in used_blocks:
                new_label = Label()
                labels[id(block)] = new_label
                instructions.append(new_label)

            for instr in block:
                # don't copy SetLineno objects
                if isinstance(instr, (Instr, ConcreteInstr)):
                    instr = instr.copy()
                    if isinstance(instr.arg, BasicBlock):
                        jumps.append(instr)
                instructions.append(instr)

        # Map to new labels
        for instr in jumps:
            instr.arg = labels[id(instr.arg)]

        bytecode = _bytecode.Bytecode()

def to_bytecode(self):
        """Convert to Bytecode."""

        used_blocks = set()
        for block in self:
            target_block = block.get_jump()
            if target_block is not None:
                used_blocks.add(id(target_block))

        labels = {}
        jumps = []
        instructions = []

        for block in self:
            if id(block) in used_blocks:
                new_label = Label()
                labels[id(block)] = new_label
                instructions.append(new_label)

            for instr in block:
                # don't copy SetLineno objects
                if isinstance(instr, (Instr, ConcreteInstr)):
                    instr = instr.copy()
                    if isinstance(instr.arg, BasicBlock):
                        jumps.append(instr)
                instructions.append(instr)

        # Map to new labels
        for instr in jumps:
            instr.arg = labels[id(instr.arg)]

        bytecode = _bytecode.Bytecode()