[IMPR] simplify list comprehension in dh()

- simplify list comprehension in dh()
- use f-string in decode() inside escapePattern2()
- fix escapePattern2 result type

Change-Id: Id2d99b040d5e7f11501fb6b1b2155695d14ce6b4
---
M pywikibot/date.py
1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/pywikibot/date.py b/pywikibot/date.py
index 07edc20..00a654e 100644
--- a/pywikibot/date.py
+++ b/pywikibot/date.py
@@ -385,18 +385,16 @@
 
 # Allows to search for '(%%)|(%d)|(%R)|...", and allows one digit 1-9 to set
 # the size of zero-padding for numbers
-_reParameters = re.compile('|'.join(f'(%[1-9]?{s})'
-                                    for s in _digitDecoders))
+_reParameters = re.compile('|'.join(f'(%[1-9]?{s})' for s in _digitDecoders))
 
 # A map of sitecode+pattern to (re matching object and corresponding decoders)
 _escPtrnCache2 = {}
 
 
-def escapePattern2(pattern: str
-                   ) -> Tuple[Pattern[str], str,
-                              List[Union[decoder_type, decoder_type]]]:
-    """
-    Convert a string pattern into a regex expression and cache.
+def escapePattern2(
+    pattern: str
+) -> Tuple[Pattern[str], str, List[decoder_type]]:
+    """Convert a string pattern into a regex expression and cache.
 
     Allows matching of any _digitDecoders inside the string.
     Returns a compiled regex object and a list of digit decoders.
@@ -427,8 +425,8 @@
         # Special case for strings that are replaced instead of decoded
         # Keep the original text for strPattern
         assert len(subpattern) < 3, (
-            'Invalid pattern {}: Cannot use zero padding size '
-            'in {}!'.format(pattern, subpattern))
+            f'Invalid pattern {pattern}: Cannot use zero padding size '
+            f'in {subpattern}!')
         return newpattern + re.escape(dec), strpattern + subpattern
 
     if pattern not in _escPtrnCache2:
@@ -515,7 +513,8 @@
     m = compPattern.match(value)
     if m:
         # decode each found value using provided decoder
-        values = [decoder[2](m[i + 1]) for i, decoder in enumerate(decoders)]
+        values = [decoder[2](m[i])
+                  for i, decoder in enumerate(decoders, start=1)]
         decValue = decf(values)
 
         assert not isinstance(decValue, str), \

