def leave_OperationDefinition(self, operation, key, parent, path, ancestors):
        variable_name_used = set()
        usages = self.context.get_recursive_variable_usages(operation)
        op_name = operation.name and operation.name.value or None

        for variable_usage in usages:
            variable_name_used.add(variable_usage.node.name.value)

        for variable_definition in self.variable_definitions:
            if variable_definition.variable.name.value is variable_name_used:
                self.context.report_error(GraphQLError(
                    self.unused_variable_message(variable_definition.variable.name.value, op_name),
                    [variable_definition]
                ))
dataset/ETHPy150Open graphql-python/graphql-core/graphql/core/validation/rules/no_unused_variables.py/NoUnusedVariables.leave_OperationDefinition/operator `not in` -> `is`