Examples using`typing.Protocol` from PEP 544

From[_PEP 333 – Python Web Server Gateway Interface v1.0_](https://peps.python.org/pep-0333/) (2003):

must have a`read()` method that takes an optional size argument.

The words "file-like" (or "file like") appear with similar implied meaning

in the Python 3.12 distribution:

- 148 times in the documentation;

- 92 times in code comments (`.py` or`.c` source files).

Also, 30 times across 21 PEPs (100, 214, 258, 282, 305, 310, 333, 368, 400, 441, 444, 578, 680, 691, 3116, 3119, 3143, 3145, 3154, 3156, 3333).

Definition in`Lib/wsgiref/types.py`:

class_Readable(Protocol):

defread(self,size:int=...,/) ->bytes:...

`typing.Protocol` definitions found with`ripgrep`:

rg"Protocol\)" -g'*.pyi'| sort

- 120 definitions on`typeshed/stdlib` (Python standard library)

- 134 definitions on`typeshed/stubs` (external packages)

-`importlib/resources/abc.py`:`class Traversable(Protocol)`

with several abstract and concrete methods, looks like an ABC but derives from`typing.Protocol`

-`asyncio/protocols.py`: defines classes`BaseProtocol`,`Protocol` etc. for network protocols

fromastimportparse,Module,FunctionDef

defdouble_any[T](x:T)->T:

deftest_double_any():

tree=parse(inspect.getsource(double_any))

matchtree:

caseModule(body=[FunctionDef(type_params=tps)]):

tv=tps[0]

asserttv.name=='T'