diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
@@ -2,11 +2,16 @@
 
 ## Code organization
 
+- `bytecode/src`: python bytecode representation in rust structures
+- `compiler/src`: python compilation to bytecode
 - `parser/src`: python lexing, parsing and ast
+- `Lib`: Carefully selected / copied files from CPython sourcecode. This is
+   the python side of the standard library.
 - `vm/src`: python virtual machine
   - `builtins.rs`: Builtin functions
   - `compile.rs`: the python compiler from ast to bytecode
   - `obj`: python builtin types
+  - `stdlib`: Standard library parts implemented in rust.
 - `src`: using the other subcrates to bring rustpython to life.
 - `docs`: documentation (work in progress)
 - `py_code_object`: CPython bytecode to rustpython bytecode converter (work in
@@ -28,8 +33,7 @@ To test rustpython, there is a collection of python snippets located in the
 
 ```shell
 $ cd tests
-$ pipenv install
-$ pipenv run pytest -v
+$ pytest -v
 ```
 
 There also are some unit tests, you can run those with cargo:

diff --git a/README.md b/README.md
@@ -81,7 +81,8 @@ Documentation HTML files can then be found in the `target/doc` directory.
 ## Contributing
 
 Contributions are more than welcome, and in many cases we are happy to guide
-contributors through PRs or on gitter.
+contributors through PRs or on gitter. Please refer to the
+[development guide](DEVELOPMENT.md) as well for tips on developments.
 
 With that in mind, please note this project is maintained by volunteers, some of
 the best ways to get started are below:

diff --git a/src/main.rs b/src/main.rs
@@ -8,11 +8,11 @@ use clap::{App, Arg, ArgMatches};
 use rustpython_compiler::{compile, error::CompileError, error::CompileErrorType};
 use rustpython_parser::error::ParseErrorType;
 use rustpython_vm::{
-    frame::Scope,
     import,
     obj::objstr,
     print_exception,
     pyobject::{ItemProtocol, PyResult},
+    scope::Scope,
     util, PySettings, VirtualMachine,
 };
 use std::convert::TryInto;

diff --git a/vm/src/builtins.rs b/vm/src/builtins.rs
@@ -22,12 +22,12 @@ use crate::obj::objtype::{self, PyClassRef};
 use rustpython_compiler::compile;
 
 use crate::eval::get_compile_mode;
-use crate::frame::Scope;
 use crate::function::{single_or_tuple_any, Args, KwArgs, OptionalArg, PyFuncArgs};
 use crate::pyobject::{
     Either, IdProtocol, IntoPyObject, ItemProtocol, PyIterable, PyObjectRef, PyResult, PyValue,
     TryFromObject, TypeProtocol,
 };
+use crate::scope::Scope;
 use crate::vm::VirtualMachine;
 
 use crate::obj::objbyteinner::PyByteInner;

diff --git a/vm/src/dictdatatype.rs b/vm/src/dictdatatype.rs
@@ -110,6 +110,7 @@ impl<T: Clone> Dict<T> {
     }
 
     /// Retrieve a key
+    #[cfg_attr(feature = "flame-it", flame("Dict"))]
     pub fn get(&self, vm: &VirtualMachine, key: &PyObjectRef) -> PyResult<Option<T>> {
         if let LookupResult::Existing(index) = self.lookup(vm, key)? {
             Ok(Some(self.unchecked_get(index)))
@@ -197,6 +198,7 @@ impl<T: Clone> Dict<T> {
     }
 
     /// Lookup the index for the given key.
+    #[cfg_attr(feature = "flame-it", flame("Dict"))]
     fn lookup(&self, vm: &VirtualMachine, key: &PyObjectRef) -> PyResult<LookupResult> {
         let hash_value = collection_hash(vm, key)?;
         let perturb = hash_value;
@@ -271,6 +273,7 @@ enum LookupResult {
     Existing(EntryIndex), // Existing record, index into entries
 }
 
+#[cfg_attr(feature = "flame-it", flame())]
 fn collection_hash(vm: &VirtualMachine, object: &PyObjectRef) -> PyResult<HashValue> {
     let raw_hash = vm._hash(object)?;
     let mut hasher = DefaultHasher::new();

diff --git a/vm/src/eval.rs b/vm/src/eval.rs
@@ -1,5 +1,5 @@
-use crate::frame::Scope;
 use crate::pyobject::PyResult;
+use crate::scope::Scope;
 use crate::vm::VirtualMachine;
 use rustpython_compiler::compile;