This is the documentation for the latest development branch of MicroPython and may refer to features that are not available in released versions.

If you are looking for the documentation for a specific release, use the drop-down menu on the left and select the desired version.

Python 3.8

Python 3.8.0 (final) was released on the 14 October 2019. The Features for 3.8 are defined in PEP 569 and a detailed description of the changes can be found in What’s New in Python 3.8.



PEP 570

Positional-only arguments

PEP 572

Assignment Expressions


PEP 574

Pickle protocol 5 with out-of-band data

PEP 578

Runtime audit hooks

PEP 587

Python Initialization Configuration

PEP 590

Vectorcall: a fast calling protocol for CPython


f-strings support = for self-documenting expressions and debugging


Other Language Changes:

A continue statement was illegal in the finally clause due to a problem with the implementation. In Python 3.8 this restriction was lifted


The bool, int , and fractions.Fraction types now have an as_integer_ratio() method like that found in float and decimal.Decimal

Constructors of int, float and complex will now use the __index__() special method, if available and the corresponding method __int__(), __float__() or __complex__() is not available

Added support of N{name} escapes in regular expressions

Dict and dictviews are now iterable in reversed insertion order using reversed()

The syntax allowed for keyword names in function calls was further restricted. In particular, f((keyword)=arg) is no longer allowed

Generalized iterable unpacking in yield and return statements no longer requires enclosing parentheses

When a comma is missed in code such as [(10, 20) (30, 40)], the compiler displays a SyntaxWarning with a helpful suggestion

Arithmetic operations between subclasses of or datetime.datetime and datetime.timedelta objects now return an instance of the subclass, rather than the base class

When the Python interpreter is interrupted by Ctrl-C (SIGINT) and the resulting KeyboardInterrupt exception is not caught, the Python process now exits via a SIGINT signal or with the correct exit code such that the calling process can detect that it died due to a Ctrl-C

Some advanced styles of programming require updating the types.CodeType object for an existing function

For integers, the three-argument form of the pow() function now permits the exponent to be negative in the case where the base is relatively prime to the modulus

Dict comprehensions have been synced-up with dict literals so that the key is computed first and the value second

The object.__reduce__() method can now return a tuple from two to six elements long

Changes to built-in modules:

asyncio has graduated from the provisional to stable API


Running python -m asyncio launches a natively async REPL

The exception asyncio.CancelledError now inherits from BaseException rather than Exception and no longer inherits from concurrent.futures.CancelledError


Added asyncio.Task.get_coro() for getting the wrapped coroutine within an asyncio.Task

Asyncio tasks can now be named, either by passing the name keyword argument to asyncio.create_task() or the create_task() event loop method, or by calling the set_name() method on the task object

Added support for Happy Eyeballs to asyncio.loop.create_connection(). To specify the behavior, two new parameters have been added: happy_eyeballs_delay and interleave.


get_objects() can now receive an optional generation parameter indicating a generation to get objects from. (Note, though, that while gc is a built-in, get_objects() is not implemented for MicroPython)


Added new function math.dist() for computing Euclidean distance between two points

Expanded the math.hypot() function to handle multiple dimensions

Added new function,, as analogous function to sum() that returns the product of a “start” value (default: 1) times an iterable of numbers

Added two new combinatoric functions math.perm() and math.comb()

Added a new function math.isqrt() for computing accurate integer square roots without conversion to floating point

The function math.factorial() no longer accepts arguments that are not int-like



Add new sys.unraisablehook() function which can be overridden to control how “unraisable exceptions” are handled