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: collection.rs
    path of file: ./repos/overlord/src/state
    
    the code of the file until where you have to start completion: use std::collections::{BTreeMap, HashMap, HashSet};

use creep::Context;
use hummer::coding::hex_encode;

use crate::types::{
    Address, AggregatedChoke, AggregatedVote, Hash, SignedChoke, SignedProposal, SignedVote,
    VoteType,
};
use crate::{error::ConsensusError, Codec, ConsensusResult};

/// A struct to collect signed proposals in each height. It sto
    
    fn gen_signed_proposal(height: u64, round: u64) -> SignedProposal<Pill> {
        let signature = gen_signature();
        let proposal = Proposal {
            height,
            round,
            content: Pill::new(),
            block_hash: gen_hash(),
            lock: None,
            proposer: gen_address(),
        };

        SignedProposal {
            signature,
            proposal,
        }
    }