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: _filter_expression.rs
    path of file: ./repos/aws-sdk-rust/sdk/glue/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 filter expression.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct FilterExpression {
    /// <p>The type of operation to perform in the expression.</p>
    pub operation: crate::types::FilterOperation,
    /// <p>Whether the expression is to be negated.</p>
    pub negated: ::std::option::Option<bool>,
    /// <p>A list of filter values.</p>
    pub values: ::std::vec::Vec<cr
    
    pub fn build(self) -> ::std::result::Result<crate::types::FilterExpression, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::FilterExpression {
            operation: self.operation.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "operation",
                    "operation was not specified but it is required when building FilterExpression",
                )
            })?,
            negated: self.negated,
            values: self.values.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "values",
                    "values was not specified but it is required when building FilterExpression",
                )
            })?,
        })
    }