fix the bug of parsing evaluator in SRL in PaddleBook.

python/paddle/v2/layer.py

@@ -235,8 +235,8 @@ def __trim_submodel__(old_submodel, layer_names, input_layer_names,
 def parse_network(output_layers, extra_layers=None):
     if not isinstance(output_layers, collections.Sequence):
         output_layers = [output_layers]
-    if extra_layers is not None and not isinstance(extra_layers,
-                                                   collections.Sequence):
+    if extra_layers is not None:
+        if not isinstance(extra_layers, collections.Sequence):
             extra_layers = [extra_layers]
     else:
         extra_layers = []

python/paddle/v2/topology.py

@@ -31,7 +31,6 @@ class Topology(object):
     def __init__(self, layers, extra_layers=None):
         def __check__(layers):
             if not isinstance(layers, collections.Sequence):
-                __check_layer_type__(layers)
                 layers = [layers]
             for layer in layers:
                 __check_layer_type__(layer)