fix missing tools prop

masque/builder/pather.py

@@ -124,6 +124,13 @@ class Pather(Builder):
         if name is not None:
             library[name] = self.pattern
 
+        if tools is None:
+            self.tools = {}
+        elif isinstance(tools, Tool):
+            self.tools = {None: tools}
+        else:
+            self.tools = dict(tools)
+
     @classmethod
     def mk(
             cls,