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: _regex_match_tuple.rs
    path of file: ./repos/aws-sdk-rust/sdk/wafregional/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.

/// <note>
/// <p>This is <b>AWS WAF Classic</b> documentation. For more information, see <a href="https://docs.aws.amazon.com/waf/latest/developerguide/classic-waf-chapter.html">AWS WAF Classic</a> in the developer guide.</p>
/// <p><b>For the latest version of AWS WAF</b>, use the AWS WAFV2 API and see the <a href="https://docs.aws.amazon.com/waf/latest/developerguide/waf-chapter.html">AWS WAF Developer Guide</a>. With the latest version, AWS WAF has a single set of endpoints for regional and global use.</p>
/// </note>
/// <p>The regular expression pattern that you want AWS WAF to search for in web requests, the location in requests that you want AWS WA
    
    pub fn build(self) -> ::std::result::Result<crate::types::RegexMatchTuple, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::RegexMatchTuple {
            field_to_match: self.field_to_match,
            text_transformation: self.text_transformation.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "text_transformation",
                    "text_transformation was not specified but it is required when building RegexMatchTuple",
                )
            })?,
            regex_pattern_set_id: self.regex_pattern_set_id.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "regex_pattern_set_id",
                    "regex_pattern_set_id was not specified but it is required when building RegexMatchTuple",
                )
            })?,
        })
    }