Program - class to show implementation of custom sequence of list

Solution

class CustomList:
    """
    This is the space to do documentation related to class.
    """
    def __init__(self):
        self.list_ = [1,2,3,4]
    def __len__(self):
        return len(self.list_)
    def __getitem__(self, i):
        if isinstance(i, int):
            if i<0:
                i = len(self.list_) + i
            
            if i<0 or i>=len(self.list_):
                raise IndexError('Invalid Input')
            else:
                return self.list_[i]