diff --git a/nac3core/src/top_level.rs b/nac3core/src/top_level.rs
index d5a3276c..29238ee6 100644
--- a/nac3core/src/top_level.rs
+++ b/nac3core/src/top_level.rs
@@ -1,7 +1,8 @@
+use std::default;
 use std::{collections::HashMap, sync::Arc};
 
 use super::typecheck::type_inferencer::PrimitiveStore;
-use super::typecheck::typedef::{SharedUnifier, Type, Unifier};
+use super::typecheck::typedef::{SharedUnifier, Type, Unifier, TypeEnum};
 use crate::symbol_resolver::SymbolResolver;
 use inkwell::{
     basic_block::BasicBlock, builder::Builder, context::Context, module::Module,
@@ -74,3 +75,132 @@ pub struct CodeGenContext<'ctx> {
     // the first one is the test_bb, and the second one is bb after the loop
     pub loop_bb: Option<(BasicBlock<'ctx>, BasicBlock<'ctx>)>,
 }
+
+pub struct TopLevelManager<'a> {
+    pub def_index: usize,
+    pub ctx: TopLevelContext,
+    pub resolver: &'a mut Box<dyn SymbolResolver>,
+    pub primitives: (PrimitiveStore, Unifier)
+}
+
+
+use rustpython_parser::ast;
+impl<'a> TopLevelManager<'a> {
+    pub fn make_primitives() -> (PrimitiveStore, Unifier) {
+        let mut unifier = Unifier::new();
+        let int32 = unifier.add_ty(TypeEnum::TObj {
+            obj_id: DefinitionId(0), // NOTE: what should it be?
+            fields: HashMap::new().into(),
+            params: HashMap::new(),
+        });
+        let int64 = unifier.add_ty(TypeEnum::TObj {
+            obj_id: DefinitionId(1), // NOTE: what should it be?
+            fields: HashMap::new().into(),
+            params: HashMap::new(),
+        });
+        let float = unifier.add_ty(TypeEnum::TObj {
+            obj_id: DefinitionId(2), // NOTE: what should it be?
+            fields: HashMap::new().into(),
+            params: HashMap::new(),
+        });
+        let bool = unifier.add_ty(TypeEnum::TObj {
+            obj_id: DefinitionId(3), // NOTE: what should it be?
+            fields: HashMap::new().into(),
+            params: HashMap::new(),
+        });
+        let none = unifier.add_ty(TypeEnum::TObj {
+            obj_id: DefinitionId(4), // NOTE: what should it be?
+            fields: HashMap::new().into(),
+            params: HashMap::new(),
+        });
+        let primitives = PrimitiveStore { int32, int64, float, bool, none };
+        crate::typecheck::magic_methods::set_primitives_magic_methods(&primitives, &mut unifier);
+        (primitives, unifier)
+    }
+
+    pub fn new(resolver: &'a mut Box<dyn SymbolResolver>) -> Self {
+        TopLevelManager {
+            def_index: 1,
+            ctx: TopLevelContext {
+                definitions: Default::default(),
+                unifiers: Default::default()
+            },
+            resolver,
+            primitives: Self::make_primitives()
+        }
+    }
+
+    pub fn register_top_level(&mut self, ast: &ast::Stmt<()>) -> Result<DefinitionId, String>{
+        match &ast.node {
+            ast::StmtKind::ClassDef {
+                name, 
+                bases,
+                keywords,
+                body,
+                decorator_list
+            } => {
+                // ancestors and type_vars are found using the `bases` field
+                let mut class_ancestors: Vec<DefinitionId> = Default::default();
+                let mut class_type_vars: Vec<Type> = Default::default();
+                for base in bases {
+                    match &base.node {
+                        ast::ExprKind::Subscript {value, slice, ..} => {
+                            match &value.node {
+                                ast::ExprKind::Name {id, ..} if id == "Generic" => {
+                                    match &slice.node {
+                                        ast::ExprKind::Tuple {elts, ..} => {
+                                            for e in elts {
+                                                class_type_vars.push(
+                                                    self.resolver.
+                                                        parse_type_name(e)
+                                                        .ok_or_else(|| "unkown base class type".to_string())?
+                                                ); // FIXME: is it correct to use this?
+                                            }
+                                        },
+                                        _ => class_type_vars.push(
+                                            self.resolver
+                                                .parse_type_name(slice)
+                                                .ok_or_else(|| "unkown base class type".to_string())?
+                                        ) // FIXME: is it correct to use this?
+                                    }
+                                },
+                                _ => return Err("only subscription on keyword Generic is allowed".into())
+                            }
+                        },
+
+                        ast::ExprKind::Name {id, ..} => {
+                            class_ancestors.push(self.resolver.get_function_def(id)) // FIXME: is it correct to use this?
+                        }
+
+                        _ => return Err("unsupported expression in the bases list".into())
+                    }
+                }
+
+                // fields and methods are determined using the `body` field
+                let class_fields: Vec<(String, Type)> = Default::default();
+                let class_methods: Vec<(String, Type, DefinitionId)> = Default::default();
+                for stmt in body {
+                    match &stmt.node {
+                        ast::StmtKind::FunctionDef {name, .. } if name != "__init__" => {
+                            let result = self.register_top_level(stmt)?;
+                            unimplemented!()
+                        },
+
+                        _ => unimplemented!()
+                    }
+                }
+
+                let defs = self.ctx.definitions.write();
+                let index = defs.len();
+
+                unimplemented!()
+            },
+            
+            ast::StmtKind::FunctionDef {name, ..} => {
+                unimplemented!()
+            }
+
+            _ => Err("only expect function definition and class definition".into())
+        }
+    }
+}
\ No newline at end of file
diff --git a/nac3core/src/typecheck/mod.rs b/nac3core/src/typecheck/mod.rs
index a75222f5..db7bcaec 100644
--- a/nac3core/src/typecheck/mod.rs
+++ b/nac3core/src/typecheck/mod.rs
@@ -1,5 +1,5 @@
 mod function_check;
-mod magic_methods;
+pub mod magic_methods;
 pub mod type_inferencer;
 pub mod typedef;
 mod unification_table;