Skip value_opts expansion when an empty list is provided (#91)

Author: caizixian

src/running/modifier.py

@@ -18,7 +18,7 @@ def __init__(self, value_opts=None, **kwargs):
         self.__original_kwargs = kwargs
         self._kwargs = copy.deepcopy(kwargs)
         self.excludes = kwargs.get("excludes", {})
-        if self.value_opts is not None:
+        if self.value_opts: # Neither None nor empty
             # Expand value opts
             for k, v in kwargs.items():
                 if type(v) is not str: