15 and 17

15.py

+# Write a function solve that rotates an n x n matrix 90 degrees clockwise in-place.
+
+def solve(matrix):
+    for i in range(int(len(matrix))):
+        for j in range(i):
+            matrix[i][j], matrix[j][i] = matrix[j][i], matrix[i][j]
+    for list in matrix:
+        list.reverse()
+    return matrix
+

17.py

+# Write a function solve that counts the number of vowels (a,e,i,o,u) in a string, ignoring case.
+
+def solve(string):
+    counter = 0
+    vowels = ["a","e","i","o","u"]
+    for char in string.lower():
+        if char in vowels:
+            counter += 1
+    return counter