DOC: clarify that assert_produces_warning can take multiple warnings

[MarcoGorelli]

Noticed in #47828 (comment)

Currently, it's possible to match multiple warnings, by passing them as a tuple. But, this isn't documented, nor do the types suggest it:

Example:

import warnings
import pytest
import pandas._testing as tm

def me():
    warnings.warn('foo', FutureWarning)
    warnings.warn('bar', UserWarning)

def test_1():
    with tm.assert_produces_warning((FutureWarning, UserWarning), match=r'foo|bar'):
        me()

So, the issue would be:

• in

  pandas/pandas/_testing/_warnings.py

  Lines 19 to 27 in 8c7b0b2

  	def assert_produces_warning(
  	expected_warning: type[Warning] | bool | None = Warning,
  	filter_level: Literal[
  	"error", "ignore", "always", "default", "module", "once"
  	] = "always",
  	check_stacklevel: bool = True,
  	raise_on_extra_warnings: bool = True,
  	match: str | None = None,
  	):

  , fix the annotation of expected_warning so it can also be Tuple[Type[Warning], ...]
• add a test to https://github.com/pandas-dev/pandas/blob/main/pandas/tests/util/test_assert_produces_warning.py for when matching multiple warnings

[Femme-js]

Hi, I want to take this forward. Can you help me proceed with it?

[MarcoGorelli]

hey @Femme-js - here's the contributing guide

what do you need help with?