More cleanup.

1 files changed, 5 insertions, 3 deletions

diff --git a/type/rate.py b/type/rate.py
index 64a4726..c365848 100644
--- a/type/rate.py
+++ b/type/rate.py
@@ -1,9 +1,13 @@
 #!/usr/bin/env python3
 
+"""A class to represent a rate of change."""
+
 from typing import Optional
 
 
 class Rate(object):
+    """A class to represent a rate of change."""
+
     def __init__(
         self,
         multiplier: Optional[float] = None,
@@ -28,9 +32,7 @@ class Rate(object):
             self.multiplier = 1.0 + percent_change / 100
             count += 1
         if count != 1:
-            raise Exception(
-                'Exactly one of percentage, percent_change or multiplier is required.'
-            )
+            raise Exception('Exactly one of percentage, percent_change or multiplier is required.')
 
     def apply_to(self, other):
         return self.__mul__(other)