def __contains__(self, item):
        """
        :param item:
            An object of the type cls._child_spec

        :return:
            A boolean if the item is contained in this SequenceOf
        """

        if item is None or item is VOID:
            return False

        if not isinstance(item, self._child_spec):
            raise TypeError(unwrap(
                '''
                Checking membership in %s is only available for instances of
                %s, not %s
                ''',
                type_name(self),
                type_name(self._child_spec),
                type_name(item)
            ))

        for child in self:
            if child == item:
                return True

        return False
def __contains__ ( self , item ) : if item is None or item is VOID : return False if not isinstance ( item , self . _child_spec ) : raise TypeError ( unwrap ( '''
                Checking membership in %s is only available for instances of
                %s, not %s
                ''' , type_name ( self ) , type_name ( self . _child_spec ) , type_name ( item ) ) ) for child in self : if child == item : return True return False
:param item:
            An object of the type cls._child_spec

        :return:
            A boolean if the item is contained in this SequenceOf