message: Minor cosmetic improvement to error message.
diff: @@ -61,7 +61,7 @@ class ListTransformer(transformer.Base):
  return templates.replace_as_expression(template, dtype_name=dtype_name)
  def _pre_populated_list(self, node):
  - raise NotImplementedError()
  + raise NotImplementedError('pre-populated lists')
  def visit_Expr(self, node):
  node = self.generic_visit(node)
  