Keeping the iterator and iterable classes seperate or not?

class Squares:
    def __init__(self, start, end):
        self.index = start
        self.end = end

    def __iter__(self):
        return self

    def __next__(self):
        if self.index >= self.end:  # Checking if index is out of the range,
            raise StopIteration     # raise StopIteration if it is.

        result = self.index**2      # First, store the square of first item, then iterate.
        self.index += 1

        return result

class Sqrt:
    def __init__(self, start, end):
        self.start = start
        self.end = end

    def __iter__(self):
        return SqrtIterator(self.start, self.end)   # Iterable classes' variables are explicitly passed.

class SqrtIterator:
    def __init__(self, start, end):
        self.index = start
        self.end = end


    def __iter__(self):
        return self

    def __next__(self):
        self.index += 1

        if self.index == self.end:
            raise StopIteration

        return (self.index - 1)**0.5    # Returning one less because we incremented at first