def unrelate(*pairs):
    """ Given any number of ``(category_name, discriminator)`` pairs
        passed as positional arguments, unrelate the associated introspectables
        from each other. The introspectable related to each pair must have
        already been added via ``.add`` or ``.add_intr``; a :exc:`KeyError`
        will result if this is not true.  An error will not be raised if any
        pair is not already related to another.

        This method is not typically called directly, instead it's called
        indirectly by :meth:`pyramid.interfaces.IIntrospector.register`
        """
