diff --git a/caduceus/sorter.py b/caduceus/sorter.py
index 88bd66b..c542ce6 100644
--- a/caduceus/sorter.py
+++ b/caduceus/sorter.py
@@ -1,5 +1,16 @@
 class SnakeSorter:
     def __init__(self, snakes):
+    '''
+    Reads in the data stored in two files and builds a list of snakes
+    
+    Args:
+        common_file: a csv file mapping common names to scientific 
+        names of snakes
+        sci_file: a csv file listing scientific names of snakes with 
+        lengths and weights 
+    
+    Returns: an unsorted list of Snake items
+    '''
         self.snakes = snakes
         self.sorted_snakes = []