Merge pull request dabeaz-course#45 from echasnovski/02-containers-fix

Make examples in '02_Containers.md' executable

Author: dabeaz

Notes/02_Working_with_data/02_Containers.md

@@ -52,9 +52,10 @@ An example when reading records from a file.
 records = []  # Initial empty list
 
 with open('Data/portfolio.csv', 'rt') as f:
+    next(f) # Skip header
     for line in f:
         row = line.split(',')
-        records.append((row[0], int(row[1])), float(row[2]))
+        records.append((row[0], int(row[1]), float(row[2])))
 ```
 
 ### Dicts as a Container