refactor: replace multiple == checks with in

To check if a variable is equal to one of many values, combine the values into a tuple and check if the variable is contained `in` it instead of checking for equality against each of the values.
This is faster, less verbose, and more readable.

python/demo_code.py

@@ -129,7 +129,7 @@ def bad_isinstance(initial_condition, object, other_obj, foo, bar, baz):
 
 
 def check(x):
-    if x == 1 or x == 2 or x == 3:
+    if x in (1, 2, 3):
         print("Yes")
     elif x != 2 or x != 3:
         print("also true")
@@ -140,7 +140,7 @@ def check(x):
     elif x == 10 or x == 20 or x == 30 and x == 40:
         print("Sweet!")
 
-    elif x == 10 or x == 20 or x == 30:
+    elif x in (10, 20, 30):
         print("Why even?")
 
 

python/utils.py

@@ -12,7 +12,7 @@ def is_even(x):
         return x % 2 == 0
 
     def is_prime(x):
-        if x == 0 or x == 1:
+        if x in (0, 1):
             return False
 
         for i in range(2, x):