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: random.rs
    path of file: ./repos/RustPython/stdlib/src
    
    the code of the file until where you have to start completion: //! Random module.

pub(crate) use _random::make_module;

#[pymodule]
mod _random {
    use crate::common::lock::PyMutex;
    use crate::vm::{
        builtins::{PyInt, PyTypeRef},
        function::OptionalOption,
        types::Constructor,
        PyObjectRef, PyPayload, PyResult, VirtualMachine,
    };
    use malachite_bigint::{BigInt, BigUint, Sign};
    use num_traits::{Signed, Zero};
    use rand::{rngs::StdRng, RngCore, SeedableRng};

    #[derive(Debug)]
    enum PyRng {
        Std(Box<StdRng>),
        MT(Box<mt19937::MT19937>),
    }

    impl Default for PyRng {
        fn default() -> Self {
            PyRng:
    
        fn getrandbits(&self, k: isize, vm: &VirtualMachine) -> PyResult<BigInt> {
            match k {
                k if k < 0 => {
                    Err(vm.new_value_error("number of bits must be non-negative".to_owned()))
                }
                0 => Ok(BigInt::zero()),
                _ => {
                    let mut rng = self.rng.lock();
                    let mut k = k;
                    let mut gen_u32 = |k| {
                        let r = rng.next_u32();
                        if k < 32 {
                            r >> (32 - k)
                        } else {
                            r
                        }
                    };

                    let words = (k - 1) / 32 + 1;
                    let wordarray = (0..words)
                        .map(|_| {
                            let word = gen_u32(k);
                            k = k.wrapping_sub(32);
                            word
                        })
                        .collect::<Vec<_>>();

                    let uint = BigUint::new(wordarray);
                    // very unlikely but might as well check
                    let sign = if uint.is_zero() {
                        Sign::NoSign
                    } else {
                        Sign::Plus
                    };
                    Ok(BigInt::from_biguint(sign, uint))
                }
            }
        }