Updated lower and upper (#2468)

* update lower and upper

* fixup! Format Python code with psf/black push

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: realDuYuanChao

Diff for: strings/lower.py

@@ -1,5 +1,4 @@
 def lower(word: str) -> str:
-
     """
     Will convert the entire string to lowecase letters
 
@@ -9,7 +8,6 @@ def lower(word: str) -> str:
     'hellzo'
     >>> lower("WHAT")
     'what'
-
     >>> lower("wh[]32")
     'wh[]32'
     >>> lower("whAT")
@@ -19,9 +17,7 @@ def lower(word: str) -> str:
     # converting to ascii value int value and checking to see if char is a capital
     # letter if it is a capital letter it is getting shift by 32 which makes it a lower
     # case letter
-    return "".join(
-        chr(ord(char) + 32) if 65 <= ord(char) <= 90 else char for char in word
-    )
+    return "".join(chr(ord(char) + 32) if "A" <= char <= "Z" else char for char in word)
 
 
 if __name__ == "__main__":

Diff for: strings/upper.py

@@ -8,17 +8,14 @@ def upper(word: str) -> str:
     'HELLO'
     >>> upper("WHAT")
     'WHAT'
-
     >>> upper("wh[]32")
     'WH[]32'
     """
 
     # converting to ascii value int value and checking to see if char is a lower letter
     # if it is a capital letter it is getting shift by 32 which makes it a capital case
     # letter
-    return "".join(
-        chr(ord(char) - 32) if 97 <= ord(char) <= 122 else char for char in word
-    )
+    return "".join(chr(ord(char) - 32) if "a" <= char <= "z" else char for char in word)
 
 
 if __name__ == "__main__":