update python notes

zk/Tuples_in_Python.md

@@ -2,10 +2,6 @@
 tags: [python, data-structures]
 ---
 
-# Tuples in Python
-
-TODO: Exapand tuple notes - give more use cases
-
 Tuples are one of the main data-structures or containers in Python. Tuples are
 useful in cases where you want to group related data and ensure that it will not
 change.
@@ -31,9 +27,13 @@ tup1 = (1, 3, 5, 7)
 print(tup1[2])
 
 # 5
-"""
 ```
 
+> Really you should know in advance how long your tuple is going to be but if
+> you just do `tup = ('shoe')` this will be processed by Python as a single
+> string. Instead if you want to indicate that the tuple may be expanded later
+> use `tup = ('shoe',)`. The comma converts it from a string to a tuple.
+
 ## Slicing
 
 ```python

zk/Type_hinting.md

@@ -4,8 +4,6 @@ tags:
   - data-types
 ---
 
-# Type hinting in Python
-
 With type hinting we can add type information to variables, functions, and
 classes. This is not enforced by the Python interpreter but can be used by
 external tools like `mypy` to check the code.
@@ -109,7 +107,7 @@ def find_index(numbers: list[int], target: int) -> Optional[int]:
 
 The function above returns an `int` or `None`.
 
-Post 3.10, we don't need to use `Optional`, we can use a union to cover the
+From 3.11, we don't need to use `Optional`, we can use a union to cover the
 `None` case. Refactoring the previous example:
 
 ```py