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: system_account.rs
    path of file: ./repos/anchor/lang/src/accounts
    
    the code of the file until where you have to start completion: //! Type validating that the account is owned by the system program

use crate
    
    fn to_account_metas(&self, is_signer: Option<bool>) -> Vec<AccountMeta> {
        let is_signer = is_signer.unwrap_or(self.info.is_signer);
        let meta = match self.info.is_writable {
            false => AccountMeta::new_readonly(*self.info.key, is_signer),
            true => AccountMeta::new(*self.info.key, is_signer),
        };
        vec![meta]
    }