Up my solution

Author: Stepleo

numpy_questions.py

@@ -40,8 +40,11 @@ def max_index(X):
     i = 0
     j = 0
 
-    # TODO
-
+    if not isinstance(X, np.ndarray):
+        raise ValueError("The input should be a numpy array.")
+    if len(X.shape) != 2:
+        raise ValueError("The input should be a 2D numpy array.")
+    i, j = np.unravel_index(np.argmax(X), X.shape)
     return i, j
 
 
@@ -64,4 +67,12 @@ def wallis_product(n_terms):
     """
     # XXX : The n_terms is an int that corresponds to the number of
     # terms in the product. For example 10000.
-    return 0.
+
+    if not isinstance(n_terms, int):
+        raise ValueError("The input should be an integer.")
+    if n_terms < 0:
+        raise ValueError("The input should be a positive integer.")
+    pi = 1
+    for i in range(1, n_terms+1):
+        pi *= (4*i**2)/(4*i**2 - 1)
+    return 2*pi