Update algorithm.py

Author: danlamanna

algorithm.py

@@ -1,5 +1,6 @@
 import os
 import random
+import sys
 
 random.seed(90210)
 
@@ -9,6 +10,9 @@
 def my_algorithm(image):
     return [random.random() for _ in range(len(diagnoses))]
 
+if not os.path.exists('/images'):
+    print('The directory /images does not exist, did you forget to mount it?', file=sys.stderr)
+    sys.exit(1)
 
 # print headers
 print(','.join(['image'] + diseases))