diff --git a/analyse_properties/main.py b/analyse_properties/main.py
index 241f3f7..d2bce05 100644
--- a/analyse_properties/main.py
+++ b/analyse_properties/main.py
@@ -83,7 +83,6 @@ class SplitColumn(beam.DoFn):
     Args:
         index : The index of the column in the list.
         split_char: The character to split the column by.
-
     """
 
     def __init__(self, index, split_char):
@@ -107,30 +106,40 @@ class CreateMappingTable(beam.DoFn):
     """
     Create a mapping table to be used as a side-input.
 
-    This mapping table has a key of an id generated across all columns and a value of
+    This mapping table has a key of an ID generated across all columns and a value of
     the raw property data.
 
-    The table is used to populate the raw property data after a GroupByKey which is done on ids only
-    in order to reduce the amount of data processed in the GroupByKey operation.
+    The table is used to populate the raw property data after a GroupByKey using
+    only the IDs in order to reduce the amount of data processed in the GroupByKey operation.
 
     Args:
-        all_columns
+        all_columns(bool): If True will use all fields to calculate the ID. If false
+            will exclude the first two.
     """
 
     def __init__(self, all_columns=False):
         self.all_columns = all_columns
 
     def process(self, element):
+        # Join the row into a string.
         unique_string = (
             ",".join(element[2:]) if not self.all_columns else ",".join(element)
         )
+        # Hash the string.
         hashed_string = hashlib.md5(unique_string.encode())
-        # add the hash as a key to the data.
+        # Format the resulting PCollection with the key of id and value of raw data.
         new_element = (hashed_string.hexdigest(), list(element))
         yield new_element
 
 
 class CreateUniquePropertyID(beam.DoFn):
+    """
+    Create a unique property ID which does not include the price and date of sale.
+
+    Uses each row of the mapping table to create a PCollection with a key of the
+    unique property ID and a value of the ID generated across all columns.
+    """
+
     def process(self, element):
         unique_string = ",".join(element[-1][2:])
         hashed_string = hashlib.md5(unique_string.encode())