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_drop_down_control.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>A control to display a dropdown list with buttons that are used to select a single value.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct FilterDropDownControl {
    /// <p>The ID of the <code>FilterDropDownControl</code>.</p>
    pub filter_control_id: ::std::string::String,
    /// <p>The title of the <code>FilterDropDownControl</code>.</p>
    pub title: ::std::string::String,
    /// <p>The source filter ID of the <code>FilterDropDownControl</code>.</p>
    pub source_filter_id: ::std::string::String,
    /// <p>The display options of the <code>FilterDropDownControl</code>.</p>
    pub display_options: ::std::option::Option<crate::types::DropDownControlDisplayOptions>,
    /// <p>The type of the <code>FilterDropDownControl</code>. Choose one of the following options:</p>
    /// <ul>
    /// <li>
    /// <p><code>MULTI_SELECT</code>: The user can select multiple entries from a dropdown menu.</p></li>
    /// <li>
    /// <p><code>SINGLE_SELECT</code>: The user can select a single entry from a dropdown menu.</p></li>
    /// </ul>
    pub r#type: ::std::option::Option<crate::types::SheetControlLis
    
    pub fn build(self) -> ::std::result::Result<crate::types::FilterDropDownControl, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::FilterDropDownControl {
            filter_control_id: self.filter_control_id.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "filter_control_id",
                    "filter_control_id was not specified but it is required when building FilterDropDownControl",
                )
            })?,
            title: self.title.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "title",
                    "title was not specified but it is required when building FilterDropDownControl",
                )
            })?,
            source_filter_id: self.source_filter_id.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "source_filter_id",
                    "source_filter_id was not specified but it is required when building FilterDropDownControl",
                )
            })?,
            display_options: self.display_options,
            r#type: self.r#type,
            selectable_values: self.selectable_values,
            cascading_control_configuration: self.cascading_control_configuration,
        })
    }