def __iter__(self) -> Iterator[tuple[int, ...]]:
        """Iterator on internal representation of control values used by the derived classes.

        Note: Be careful that the terms iterated upon by this iterator will have different
        meaning based on the implementation. For example:
        >>> print(*cirq.ProductOfSums([(0, 1), (0,)]))
        (0, 1) (0,)
        >>> print(*cirq.SumOfProducts([(0, 0), (1, 0)]))
        (0, 0) (1, 0)
        """
Iterator on internal representation of control values used by the derived classes.

        Note: Be careful that the terms iterated upon by this iterator will have different
        meaning based on the implementation. For example:
        >>> print(*cirq.ProductOfSums([(0, 1), (0,)]))
        (0, 1) (0,)
        >>> print(*cirq.SumOfProducts([(0, 0), (1, 0)]))
        (0, 0) (1, 0)
        
cirq-core/cirq/ops/control_values.py