docstrings to format_as function

theano/tensor/tensor_grad.py

@@ -25,6 +25,14 @@ _logger = logging.getLogger('theano.tensor.tensor_grad')
 
 
 def format_as(use_list, use_tuple, outputs):
+    """
+    Formats the outputs according to the flags `use_list` and `use_tuple`.
+    If `use_list` is True, `outputs` is returned as a list (if `outputs`
+    is not a list or a tuple then it is converted in a one element list)
+    If `use_tuple` is True, `outputs` is returned as a tuple (if `outputs`
+    is not a list or a tuple then it is converted into a one element tuple)
+    Otherwise (if both flags are false), `outputs` is returned.
+    """
     if (use_list or use_tuple) and not isinstance(outputs, (list, tuple)):
         if use_list:
             return [outputs]