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: mutator.rs
    path of file: ./repos/diem/language/move-prover/mutation/src
    
    the code of the file until where you have to start completion: // Copyright (c) The Diem Core Contributors
// SPDX-License-Identifier: Apache-2.0

// Functions for running move programs with mutations and reporting errors if found

use bytecode::{mutation_tester::MutationManager, options::ProverOptions};
use clap::{App, Arg};
use codespan_reporting::term::termcolor::{ColorChoice, Standar
    
    fn mutate_function(&mut self, fun: FunctionEnv<'_>) -> anyhow::Result<bool> {
        // Scope verification to the given function
        let env = fun.module_env.env;
        self.options.prover.verify_scope = VerificationScope::Only(fun.get_full_name_str());
        ProverOptions::set(env, self.options.prover.clone());
        let (duration, status) = self.run_mutated_function(fun.module_env.env)?;

        let mutated = env
            .get_extension::<MutationManager>()
            .map(|e| e.mutated)
            .unwrap_or(false);
        if mutated {
            print!("mutated function {} ..", fun.get_full_name_str());
            std::io::stdout().flush()?;
            println!("\x08\x08{:.3}s {}.", duration.as_secs_f64(), status);
        }
        Ok(mutated)
    }