        fn add_manager(ref self: ContractState, new_manager: ContractAddress) -> bool {
            let caller = get_caller_address();
@>            assert(self.chakra_managers.read(caller) == 1, Errors::NOT_MANAGER);
            assert(self.chakra_managers.read(new_manager) == 0, Errors::ALREADY_MANAGER);


            self.chakra_managers.write(new_manager, 1);
            self
                .emit(
                    ManagerAdded {
                        operator: caller, new_manager: new_manager, added_at: get_block_timestamp()
                    }
                );
            return self.chakra_managers.read(new_manager) == 1;
        }
        fn add_operator(ref self: ContractState, new_operator: ContractAddress) -> bool {
            let caller = get_caller_address();
@>            assert(self.chakra_managers.read(caller) == 1, Errors::NOT_MANAGER);
            assert(self.chakra_operators.read(new_operator) == 0, Errors::ALREADY_OPERATOR);


            self.chakra_operators.write(new_operator, 1);
            self
                .emit(
                    OperatorAdded { new_operator: new_operator, added_at: get_block_timestamp() }
                );
            return self.chakra_operators.read(new_operator) == 1;
        }

        fn mint_to(ref self: ContractState, to: ContractAddress, amount: u256) -> bool {
            let caller = get_caller_address();
@>            assert(self.chakra_operators.read(caller) == 1, Errors::NOT_OPERATOR);
            let old_balance = self.erc20.balance_of(to);
            self.erc20.mint(to, amount);
            let new_balance = self.erc20.balance_of(to);
            return new_balance == old_balance + amount;
        }
    fn add_manager(ref self: ContractState, new_manager: ContractAddress) -> bool {
            let caller = get_caller_address();
-            assert(self.chakra_managers.read(caller) == 1, Errors::NOT_MANAGER);
+            self.ownable.assert_only_owner();
            assert(self.chakra_managers.read(new_manager) == 0, Errors::ALREADY_MANAGER);


            self.chakra_managers.write(new_manager, 1);
            self
                .emit(
                    ManagerAdded {
                        operator: caller, new_manager: new_manager, added_at: get_block_timestamp()
                    }
                );
            return self.chakra_managers.read(new_manager) == 1;
        }
    fn add_operator(ref self: ContractState, new_operator: ContractAddress) -> bool {
            let caller = get_caller_address();
-            assert(self.chakra_managers.read(caller) == 1, Errors::NOT_MANAGER);
+            self.ownable.assert_only_owner();
            assert(self.chakra_operators.read(new_operator) == 0, Errors::ALREADY_OPERATOR);


            self.chakra_operators.write(new_operator, 1);
            self
                .emit(
                    OperatorAdded { new_operator: new_operator, added_at: get_block_timestamp() }
                );
            return self.chakra_operators.read(new_operator) == 1;
        }
