Fix beneficiaries handling in Comment_options

Fixes #20

beembase/operations.py

@@ -356,12 +356,12 @@ class Comment_options(GrapheneObject):
             kwargs = args[0]
 
         # handle beneficiaries
+        if "beneficiaries" in kwargs and kwargs['beneficiaries']:
+            kwargs['extensions'] = [[0, {'beneficiaries': kwargs['beneficiaries']}]]
+
         extensions = Array([])
-        beneficiaries = kwargs.get('beneficiaries')
-        if beneficiaries and type(beneficiaries) == list:
-            ext_obj = [0, {'beneficiaries': beneficiaries}]
-            ext = CommentOptionExtensions(ext_obj)
-            extensions = Array([ext])
+        if "extensions" in kwargs and kwargs["extensions"]:
+            extensions = Array([CommentOptionExtensions(o) for o in kwargs["extensions"]])
 
         super(Comment_options, self).__init__(
             OrderedDict([