You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: _backup_rule.rs
    path of file: ./repos/aws-sdk-rust/sdk/backup/src/types
    
    the code of the file until where you have to start completion: // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.

/// <p>Specifies a scheduled task used to back up a selection of resources.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq)]
pub struct BackupRule {
    /// <p>A display name for a backup rule. Must contain 1 to 50 alphanumeric or '-_.' characters.</p>
    pub rule_name: ::std::string::String,
    /// <p>The name of a logical container whe
    
    pub fn build(self) -> ::std::result::Result<crate::types::BackupRule, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::BackupRule {
            rule_name: self.rule_name.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "rule_name",
                    "rule_name was not specified but it is required when building BackupRule",
                )
            })?,
            target_backup_vault_name: self.target_backup_vault_name.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "target_backup_vault_name",
                    "target_backup_vault_name was not specified but it is required when building BackupRule",
                )
            })?,
            schedule_expression: self.schedule_expression,
            start_window_minutes: self.start_window_minutes,
            completion_window_minutes: self.completion_window_minutes,
            lifecycle: self.lifecycle,
            recovery_point_tags: self.recovery_point_tags,
            rule_id: self.rule_id,
            copy_actions: self.copy_actions,
            enable_continuous_backup: self.enable_continuous_backup,
            schedule_expression_timezone: self.schedule_expression_timezone,
        })
    }