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: module_tree.rs
    path of file: ./repos/prusti-dev/jni-gen/src
    
    the code of the file until where you have to start completion: // Â© 2019, ETH Zurich
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

use std::collections::BTreeMap;

#[derive(Debug)]
pub enum ModuleTree {
    Node(BTreeMap<String, ModuleTree>),
    Leaf,
}

#[allow(clippy::derivable_impls)]
impl Default for ModuleTree {
    fn default() -> Self {
        ModuleTree::Node(BTreeMap::new())
    }
}

impl ModuleTree {
    pub fn insert<I>(self, path: I) -> Self
    where
        I: IntoIterator<Item = String>,
    {
        let mut path_iter = path.into_iter();
        let curr_name = path_iter.next();
        match curr_name {
            Some(name) => match self {
                ModuleTree::Leaf => {
                    let mut modules = BTreeM
    
    pub fn get_paths(&self) -> Vec<Vec<String>> {
        match *self {
            ModuleTree::Leaf => vec![],
            ModuleTree::Node(ref modules) => {
                let mut result: Vec<Vec<String>> = vec![];
                for (name, sub_modules) in modules.iter() {
                    let mut sub_results: Vec<Vec<String>> = sub_modules.get_paths();
                    if !sub_results.is_empty() {
                        for sub_result in &mut sub_results {
                            let mut tmp = vec![name.to_string()];
                            tmp.append(sub_result);
                            *sub_result = tmp;
                        }
                    } else {
                        sub_results = vec![vec![name.to_string()]];
                    }
                    result.extend(sub_results);
                }
                result
            }
        }
    }