message: Fix typo
  `values` is not defined.
diff: @@ -1492,7 +1492,7 @@ class BaseStagingArea(object):
  # Sanity check number of values
  if not len(vals) <= len(self._dtypes):
  raise ValueError("Unexpected number of inputs '%s' vs '%s'" % (
  - len(values), len(self._dtypes)))
  + len(vals), len(self._dtypes)))
  tensors = []
  