diff --git a/nodes/2.x/python/All Elements Of Category+.py b/nodes/2.x/python/All Elements Of Category+.py
index 44a809bf..c808bd5a 100644
--- a/nodes/2.x/python/All Elements Of Category+.py	
+++ b/nodes/2.x/python/All Elements Of Category+.py	
@@ -8,8 +8,10 @@
 from RevitServices.Persistence import DocumentManager
 
 def ElementsByCategory(bic, doc):
-	collector = FilteredElementCollector(doc).OfCategory(bic).WhereElementIsNotElementType()
-	return collector.ToElements()
+	if bic:
+		collector = FilteredElementCollector(doc).OfCategory(bic).WhereElementIsNotElementType()
+		return collector.ToElements()
+	else: return []
 
 inputdoc = UnwrapElement(IN[2])
 if not inputdoc: doc = DocumentManager.Instance.CurrentDBDocument
diff --git a/nodes/2.x/python/All Family Types Of Category.py b/nodes/2.x/python/All Family Types Of Category.py
index 93f6ade2..efa9f4a5 100644
--- a/nodes/2.x/python/All Family Types Of Category.py	
+++ b/nodes/2.x/python/All Family Types Of Category.py	
@@ -8,8 +8,10 @@
 from RevitServices.Persistence import DocumentManager
 
 def ElementTypesByCategory(bic, doc):
-	collector = FilteredElementCollector(doc).OfCategory(bic).WhereElementIsElementType()
-	return collector.ToElements()
+	if bic:
+		collector = FilteredElementCollector(doc).OfCategory(bic).WhereElementIsElementType()
+		return collector.ToElements()
+	else: return []
 
 inputdoc = UnwrapElement(IN[2])
 if not inputdoc: doc = DocumentManager.Instance.CurrentDBDocument