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: hdescobarh.rs
    path of file: ./repos/retos-programacion-2023/Retos/Reto #14 - OCTAL Y HEXADECIMAL [Fácil]/rust
    
    the code of the file until where you have to start completion: // Define the accepted bases and their respective digits set
pub enum Base {
    Octal([char; 8]),
    Hexadecimal([char; 16]),
}

impl Base {
    pub fn value_at_index(&self, index: usize) ->
    
pub fn convert_from_decimal(to: Base, decimal_number: isize) -> String {
    // recover and remove sign
    let sign: &str = {
        if decimal_number < 0 {
            "-"
        } else {
            ""
        }
    };
    let mut current_dec_value: usize = decimal_number.unsigned_abs();

    // convert and put in correct order the output
    let mut transformed: String = String::new();
    while current_dec_value > 0 {
        let remainer = current_dec_value.rem_euclid(to.base_size());
        transformed.push(*to.value_at_index(remainer));
        current_dec_value = current_dec_value.div_euclid(to.base_size());
    }
    transformed = transformed.chars().rev().collect();

    // format literal representation
    format!("{sign}{symbol}{transformed}", symbol = to.format_symbol())
}