Solution to problem 6 part 2 in Python (failed mypy :()

src/P6.py

@@ -66,7 +66,7 @@ with open("files/P6.txt", "r") as f:
 def part_1() -> None:
     counts: int = 0
     for answers_group in answers_groups:
-        q = len(
+        yes = len(
             set(
                 [
                     answer
@@ -75,10 +75,64 @@ def part_1() -> None:
                 ]
             )
         )
-        counts += q
+        counts += yes
+
+    print(f"The sum of counts is {counts}")
+
+
+# --- Part Two ---
+
+# As you finish the last group's customs declaration, you notice that you
+# misread one word in the instructions:
+
+# You don't need to identify the questions to which anyone answered "yes"; you
+# need to identify the questions to which everyone answered "yes"!
+
+# Using the same example as above:
+
+# abc
+
+# a
+# b
+# c
+
+# ab
+# ac
+
+# a
+# a
+# a
+# a
+
+# b
+
+# This list represents answers from five groups:
+
+#     In the first group, everyone (all 1 person) answered "yes" to 3
+# questions: a, b, and c.
+#     In the second group, there is no question to which everyone answered
+# "yes".
+#     In the third group, everyone answered yes to only 1 question, a. Since
+# some people did not answer "yes" to b or c, they don't count.
+#     In the fourth group, everyone answered yes to only 1 question, a.
+#     In the fifth group, everyone (all 1 person) answered "yes" to 1 question,
+# b.
+
+# In this example, the sum of these counts is 3 + 0 + 1 + 1 + 1 = 6.
+
+# For each group, count the number of questions to which everyone answered
+# "yes". What is the sum of those counts?
+
+
+def part_2() -> None:
+    counts: int = 0
+    for answers_group in answers_groups:
+        yes = len(set.intersection(*map(set, answers_group)))
+        counts += yes
 
     print(f"The sum of counts is {counts}")
 
 
 if __name__ == "__main__":
     part_1()
+    part_2()