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: _table_lf_tag_policy_and_permissions.rs
    path of file: ./repos/aws-sdk-rust/sdk/dataexchange/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>The LF-tag policy and permissions that apply to table resources.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct TableLfTagPolicyAndPermissions {
    /// <p>A list of LF-tag conditions that apply to table resources.</p>
    pub expression: ::std::vec::Vec<crate::types::LfTag>,
    /// <p>The permissions granted to subscribers on table resources.</p>
    pub permissions: ::std::vec::Vec<crate::types::TableTagPolicyLfPermission>,
}
impl TableLfTagPolicyAndPermissions {
    /// <p>A list of LF-tag conditions that apply to table resources.</p>
    pub fn expression(&self) -> &[crate::types::LfTag] {
        use std::ops::Deref;
        self.expression.deref()
    }
    /// <p>The permissi
    
    pub fn build(self) -> ::std::result::Result<crate::types::TableLfTagPolicyAndPermissions, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::TableLfTagPolicyAndPermissions {
            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 TableLfTagPolicyAndPermissions",
                )
            })?,
            permissions: self.permissions.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "permissions",
                    "permissions was not specified but it is required when building TableLfTagPolicyAndPermissions",
                )
            })?,
        })
    }