Update changelog for 0.4.0

[osm/N2VC.git] / juju / constraints.py

diff --git a/juju/constraints.py b/juju/constraints.py
index 97529e4..998862d 100644 (file)
--- a/juju/constraints.py
+++ b/juju/constraints.py
@@ -21,6 +21,7 @@ import re
 MEM = re.compile('^[1-9][0-9]*[MGTP]$')
 
 # Multiplication factors to get Megabytes
+# https://github.com/juju/juju/blob/master/constraints/constraints.go#L666
 FACTORS = {
     "M": 1,
     "G": 1024,
@@ -31,16 +32,14 @@ FACTORS = {
 SNAKE1 = re.compile(r'(.)([A-Z][a-z]+)')
 SNAKE2 = re.compile('([a-z0-9])([A-Z])')
 
+
 def parse(constraints):
     """
     Constraints must be expressed as a string containing only spaces
     and key value pairs joined by an '='.
 
     """
-    if constraints is None:
-        return None
-
-    if constraints == "":
+    if not constraints:
         return None
 
     if type(constraints) is dict: