added local maxima function

hands_on/local_maxima/local_maxima.py

@@ -4,12 +4,18 @@ def find_maxima(x):
     Input arguments:
     x -- 1D list of real numbers
 
+
     Output:
     idx -- list of indices of the local maxima in x
     """
-    return []
+    maxima = []
+    for index in range(len(x)-2):
+        if x[index+1] > x[index] and x[index +1] > x[index+2]:
+            maxima.append(index+1)
+    
+    return maxima
 
 
 if __name__ == "__main__":
-    x = [1, 2, 3]
+    x = [1, 2, 2, 1]
     print(find_maxima(x))