A model for this must provide:

template <class ForwardIterator>
Bounded_side fo ( ForwardIterator first , ForwardIterator last , Kernel::Point_d p )
returns the relative position of point p to the sphere defined by A = tuple [first,last). The order of the points of A does not matter.
Precondition: orientation(first,last) is not ZERO.
Requirement: The value type of ForwardIterator is Kernel::Point_d.