Set the Python file maximum line length to 88 characters (#2122)

* flake8 --max-line-length=88

* fixup! Format Python code with psf/black push

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

conversions/decimal_to_hexadecimal.py

@@ -23,7 +23,8 @@ values = {
 
 def decimal_to_hexadecimal(decimal):
     """
-        take integer decimal value, return hexadecimal representation as str beginning with 0x
+        take integer decimal value, return hexadecimal representation as str beginning
+        with 0x
         >>> decimal_to_hexadecimal(5)
         '0x5'
         >>> decimal_to_hexadecimal(15)