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: candidate_uncles.rs
    path of file: ./repos/ckb/tx-pool/src/block_assembler
    
    the code of the file until where you have to start completion: use ckb_types::core::{BlockNumber, EpochExt, UncleBlockView};
use std::collections::{btree_map::Entry, BTreeMap, HashSet};

use ckb_snapshot::Snapshot;
use ckb_store::Ch
    
    pub fn insert(&mut self, uncle: UncleBlockView) -> bool {
        let number: BlockNumber = uncle.header().number();
        if self.count >= MAX_CANDIDATE_UNCLES {
            let first_key = *self.map.keys().next().expect("length checked");
            if number > first_key {
                if let Some(set) = self.map.remove(&first_key) {
                    self.count -= set.len();
                }
            } else {
                return false;
            }
        }

        let set = self.map.entry(number).or_default();
        if set.len() < MAX_PER_HEIGHT {
            let ret = set.insert(uncle);
            if ret {
                self.count += 1;
            }
            ret
        } else {
            false
        }
    }