Fix a typo before

python/paddle/v2/optimizer.py

@@ -16,6 +16,7 @@ __all__ = [
 
 class Optimizer(object):
     def __init__(self, **kwargs):
+        import py_paddle.swig_paddle as swig_api
         if 'batch_size' in kwargs:
             del kwargs['batch_size']  # not important for python library.
 
@@ -24,8 +25,6 @@ class Optimizer(object):
 
         self.__opt_conf_proto__ = config_parser_utils.parse_optimizer_config(
             __impl__)
-        if swig_api is None:
-            raise RuntimeError("paddle.v2 currently need swig_paddle")
         self.__opt_conf__ = swig_api.OptimizationConfig.createFromProto(
             self.__opt_conf_proto__)