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: port_table.rs
    path of file: ./repos/rCore-Tutorial-v3/os/src/net
    
    the code of the file until where you have to start completion: use alloc::{sync::Arc, vec::Vec};
use lazy_static::laz
    
pub fn port_acceptable(listen_index: usize) -> bool {
    let mut listen_table = LISTEN_TABLE.exclusive_access();
    assert!(listen_index < listen_table.len());

    let listen_port = listen_table[listen_index].as_mut();
    listen_port.map_or(false, |x| x.receivable)
}