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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def set_items_sequential(self, sequential):
 """Sets the items sequential flag. arg: sequential (boolean):
 ``true`` if the items are taken sequentially, ``false`` if the items can be skipped and revisited raise: InvalidArgument - ``sequential`` is invalid raise: NoAccess - ``Metadata.isReadOnly()`` is ``true`` *compliance: mandatory -- This method must be implemented.* """

        # Implemented from template for osid.resource.ResourceForm.set_group_template
        if self.get_items_sequential_metadata().is_read_only():
            raise errors.NoAccess()
        if not self._is_valid_boolean(sequential):
            raise errors.InvalidArgument()
        self._my_map['itemsSequential'] = sequential