diff --git a/seq2seq/training/utils.py b/seq2seq/training/utils.py
index 9451d57c..e73ebac0 100644
--- a/seq2seq/training/utils.py
+++ b/seq2seq/training/utils.py
@@ -115,7 +115,7 @@ def cell_from_spec(cell_classname, cell_params):
   cell_class = locate(cell_classname) or getattr(rnn_cell, cell_classname)
 
   # Make sure additional arguments are valid
-  cell_args = set(inspect.getargspec(cell_class.__init__).args[1:])
+  cell_args = set(inspect.signature(cell_class.__init__).parameters)
   for key in cell_params.keys():
     if key not in cell_args:
       raise ValueError(