fix bug where datasources with empty sets would generate the wrong response

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "random-sets"
-version = "0.1.0"
+version = "0.1.1"
 description = "A small library of helper classes for dealing with random data using weighted distributions"
 authors = ["evilchili <evilchili@gmail.com>"]
 readme = "README.md"

random_sets/datasources.py

@@ -124,7 +124,7 @@ class DataSource:
         # If there is no data for the specified option, stop now.
         flattened = [option]
         if not self.data[option]:
-            flattened
+            return random.choice(flattened) if rand else flattened
 
         if hasattr(self.data[option], 'keys'):
             # if the option is a dict, we assume the values are lists; we select a random item