when does ':' show up in function arguments / keyword arguments in python?

Question

I've been coding in python for quite a while but I came across a piece of code which got me really confused, as I've never seen expressions like this before:

class A(object):

    def __init__(self, config:dict, pool_args: dict=None, background: bool=True, **kwargs):
         self._config = config
         self._pool_args = pool_args
          ...

so what is this type of syntax: config:dict and pool_args: dict=None inside the function argument brackets?
Are they used often? I've really never seen this before.

https://docs.python.org/3/library/typing.html This provides more details — Sheldore, May 28 '19 at 00:38

score 1 · Answer 1 · answered May 28 '19 at 00:37

1

These are type hints. See this for more details: https://www.python.org/dev/peps/pep-0484/

answered May 28 '19 at 00:37

davejagoda

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when does ':' show up in function arguments / keyword arguments in python?

1 Answers1