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: create.rs
    path of file: ./repos/wrangler-legacy/src/commands/kv/namespace
    
    the code of the file until where you have to start completion: use anyhow::Result;
use regex::Regex;

use crate::commands::kv;
use crate::http;
use crate::kv::namespace::create;
use crate::settings::global_user::GlobalUser;
use crate::settings::toml::{ConfigKvNamespace, KvNamespace, Manifest};
use crate::terminal::message::{Message, StdOut};
pub fn run(
    manifest: &Manifest,
    is_preview: bool,
    env: Option<&str>,
    user: &GlobalUser,
    binding: &str,
) -> Result<()> {
    let accoun
    
    fn it_messages_about_preview() {
        let new_namespace = KvNamespace {
            id: "new_preview_id".to_string(),
            binding: "FOO".to_string(),
        };

        let all_namespaces = Some(vec![ConfigKvNamespace {
            binding: "FOO".to_string(),
            id: Some("existing_production_id".to_string()),
            preview_id: None,
        }]);

        let env = None;

        let is_preview = true;

        let msg =
            toml_modification_instructions(new_namespace, all_namespaces.as_ref(), env, is_preview);
        assert!(msg.contains("{ binding = \"FOO\", preview_id = \"new_preview_id\", id = \"existing_production_id\" }"));
        assert!(!msg.contains("kv_namespaces = ["));
    }