Add py39 target in Black's configuration, bump Black to 21.5b2

.pre-commit-config.yaml

@@ -9,7 +9,7 @@ repos:
     -   id: absolufy-imports
         files: ^pandas/
 -   repo: https://github.com/python/black
-    rev: 20.8b1
+    rev: 21.5b2
     hooks:
     -   id: black
 -   repo: https://github.com/codespell-project/codespell

doc/source/development/contributing_codebase.rst

@@ -169,7 +169,7 @@ submitting code to run the check yourself::
 to auto-format your code. Additionally, many editors have plugins that will
 apply ``black`` as you edit files.
 
-You should use a ``black`` version 20.8b1 as previous versions are not compatible
+You should use a ``black`` version 21.5b2 as previous versions are not compatible
 with the pandas codebase.
 
 One caveat about ``git diff upstream/master -u -- "*.py" | flake8 --diff``: this

environment.yml

@@ -18,7 +18,7 @@ dependencies:
   - cython>=0.29.21
 
   # code checks
-  - black=20.8b1
+  - black=21.5b2
   - cpplint
   - flake8=3.9.2
   - flake8-bugbear=21.3.2  # used by flake8, find likely bugs

pandas/_config/config.py

@@ -189,7 +189,7 @@ def get_default_val(pat: str):
 
 
 class DictWrapper:
-    """ provide attribute-style access to a nested dict"""
+    """provide attribute-style access to a nested dict"""
 
     def __init__(self, d: dict[str, Any], prefix: str = ""):
         object.__setattr__(self, "d", d)
@@ -571,7 +571,7 @@ def _get_root(key: str) -> tuple[dict[str, Any], str]:
 
 
 def _is_deprecated(key: str) -> bool:
-    """ Returns True if the given option has been deprecated """
+    """Returns True if the given option has been deprecated"""
     key = key.lower()
     return key in _deprecated_options
 
@@ -643,7 +643,7 @@ def _warn_if_deprecated(key: str) -> bool:
 
 
 def _build_option_description(k: str) -> str:
-    """ Builds a formatted description of a registered option and prints it """
+    """Builds a formatted description of a registered option and prints it"""
     o = _get_registered_option(k)
     d = _get_deprecated_option(k)
 
@@ -667,7 +667,7 @@ def _build_option_description(k: str) -> str:
 
 
 def pp_options_list(keys: Iterable[str], width=80, _print: bool = False):
-    """ Builds a concise listing of available options, grouped by prefix """
+    """Builds a concise listing of available options, grouped by prefix"""
     from itertools import groupby
     from textwrap import wrap