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: _conditional_formatting_icon_set.rs
    path of file: ./repos/aws-sdk-rust/sdk/quicksight/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>Formatting configuration for icon set.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq)]
pub struct ConditionalFormattingIconSet {
    /// <p>The expression that determines the formatting configuration for the icon set.</p>
    pub expression: ::std::string::String,
    /// <p>Determines the icon set type.</p>
    pub icon_set_type: ::std::option::Option<crate::types::ConditionalFormattingIconSetType>,
}
imp
    
    pub fn build(self) -> ::std::result::Result<crate::types::ConditionalFormattingIconSet, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::ConditionalFormattingIconSet {
            expression: self.expression.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "expression",
                    "expression was not specified but it is required when building ConditionalFormattingIconSet",
                )
            })?,
            icon_set_type: self.icon_set_type,
        })
    }