The MicroPython project aims to put an implementation of Python 3.x on microcontrollers and small embedded systems. MicroPython implements the entire Python 3.4 syntax (including exceptions, with, yield from, etc., and additionally async/await keywords from Python 3.5). The following core datatypes are provided: str (including basic Unicode support), bytes, bytearray, tuple, list, dict, set, frozenset, array.array, collections.namedtuple, classes and instances. Builtin modules include sys, time, and struct, etc. Select ports have support for _thread module (multithreading). Note that only a subset of Python 3 functionality is implemented for the data types and modules. MicroPython can execute scripts in textual source form or from precompiled bytecode, in both cases either from an on-device filesystem or "frozen" into the MicroPython executable.