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: mod.rs
    path of file: ./repos/ron/src/ser
    
    the code of the file until where you have to start completion: use std::fmt;

use serde::{ser, ser::Serialize};
use serde_derive::{Deserialize, Serialize};
use unicode_ident::is_xid_continue;

use crate::{
    error::{Error, Result},
    extensions::Extensions,
    options::Options,
    parse::{is_ident_first_char, is_ident_raw_char, is_whitespace_char, LargeSInt, LargeUInt},
};

mod raw;
#[cfg(test)]
mod tests;
mod value;

/// Serializes `value` into `writer`.
///
/// This f
    
    fn serialize_tuple(self, len: usize) -> Result<Self::SerializeTuple> {
        let old_newtype_variant = self.newtype_variant;
        self.newtype_variant = false;
        self.implicit_some_depth = 0;

        if !old_newtype_variant {
            self.output.write_char('(')?;
        }

        if self.separate_tuple_members() {
            self.is_empty = Some(len == 0);

            self.start_indent()?;
        }

        Ok(Compound::new(self, old_newtype_variant))
    }