code: func (c *CloudFormation) DeleteStackInstances(input *DeleteStackInstancesInput) (*DeleteStackInstancesOutput, error) {
  	req, out := c.DeleteStackInstancesRequest(input)
  	return out, req.Send()
  }
docs: // DeleteStackInstances API operation for AWS CloudFormation.
  //
  // Deletes stack instances for the specified accounts, in the specified regions.
  //
  // Returns awserr.Error for service API and SDK errors. Use runtime type assertions
  // with awserr.Error's Code and Message methods to get detailed information about
  // the error.
  //
  // See the AWS API reference guide for AWS CloudFormation's
  // API operation DeleteStackInstances for usage and error information.
  //
  // Returned Error Codes:
  //   * ErrCodeStackSetNotFoundException "StackSetNotFoundException"
  //   The specified stack set doesn't exist.
  //
  //   * ErrCodeOperationInProgressException "OperationInProgressException"
  //   Another operation is currently in progress for this stack set. Only one operation
  //   can be performed for a stack set at a given time.
  //
  //   * ErrCodeOperationIdAlreadyExistsException "OperationIdAlreadyExistsException"
  //   The specified operation ID already exists.
  //
  //   * ErrCodeStaleRequestException "StaleRequestException"
  //   Another operation has been performed on this stack set since the specified
  //   operation was performed.
  //
  //   * ErrCodeInvalidOperationException "InvalidOperationException"
  //   The specified operation isn't valid.
  //
  // See also, https://docs.aws.amazon.com/goto/WebAPI/cloudformation-2010-05-15/DeleteStackInstances