Why VS code shows it's invalid syntax for a python code using abc Module - python3.8.0

Question

See code below, type the same as written in Book Data Structur and Algorthm in Python, I am new to programming, can someone help?

from abc import ABCMeta, abstractmethod

class Sequence(metaclass=ABCMeta):

    @abstractmethod
    def __len__(self):


    @abstractmethod
    def __getitem__(self, j): **# Here there is red wave line under 'def'**


    def __contains__(self, val):
        for j in range(len(self)):
            if self[j] == val:
                return True
        return False

    def index(self, val):
        for j in range(len(self)):
            if self[j] == val:
                return j
        raise ValueError('value not in sequence')

    def count(self, val):
        k = 0
        for j in range(len(self)):
            if self[j] == val:
                k += 1
        return k

Answer 1

In python Indentation is important also there is # used for comment

please go through the following code which is error-free

from abc import ABCMeta, abstractmethod

class Sequence(metaclass=ABCMeta):

    @abstractmethod
    def __len__(self):
        pass


    @abstractmethod
    def __getitem__(self, j):
        #**# Here there is red wave line under 'def'**
        pass
    def __contains__(self, val):

        for j in range(len(self)):
            if self[j] == val:
                return True
        return False

    def index(self, val):
        for j in range(len(self)):
            if self[j] == val:
                return j
        raise ValueError('value not in sequence')

    def count(self, val):
        k = 0
        for j in range(len(self)):
            if self[j] == val:
                k += 1
        return ks 

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