from_verilog is updated: A bug of importing Case object is fixed.

Author: shtaxxx

veriloggen/from_verilog.py

@@ -618,7 +618,7 @@ def visit_CasexStatement(self, node):
         return case
 
     def visit_Case(self, node):
-        condition = tuple([ self.visit(c) for c in node.cond ])
+        condition = tuple([ self.visit(c) for c in node.cond ]) if node.cond else [ None ]
         statement = to_tuple(self.visit(node.statement))
         when = vtypes.When(*condition)
         when = when(*statement)