Fix API example code (#18176)

The fixed APIs:
6 Methods in paddle.fluid.io.PyReader
paddle.fluid.layers.Preprocessor
paddle.fluid.layers.py_reader
paddle.fluid.io.save_params
paddle.fluid.io.save_persistables

test=develop
test=document_preview

paddle/fluid/API.spec

@@ -49,19 +49,19 @@ paddle.fluid.BuildStrategy.ReduceStrategy.__init__ __init__(self: paddle.fluid.c
 paddle.fluid.BuildStrategy.__init__ __init__(self: paddle.fluid.core_avx.ParallelExecutor.BuildStrategy) -> None
 paddle.fluid.gradients (ArgSpec(args=['targets', 'inputs', 'target_gradients', 'no_grad_set'], varargs=None, keywords=None, defaults=(None, None)), ('document', 'e2097e1e0ed84ae44951437bfe269a1b'))
 paddle.fluid.io.save_vars (ArgSpec(args=['executor', 'dirname', 'main_program', 'vars', 'predicate', 'filename'], varargs=None, keywords=None, defaults=(None, None, None, None)), ('document', '869104f47e6fd21d897c3fcc426aa942'))
-paddle.fluid.io.save_params (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', '07ffd5351b30cf47172ccfd61bd0de6f'))
-paddle.fluid.io.save_persistables (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', '9141bb5f32caf7975eb3fd88c8a1b2da'))
+paddle.fluid.io.save_params (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', '046d7c43d67e08c2660bb3bd7e081015'))
+paddle.fluid.io.save_persistables (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', 'ffcee38044975c29f2ab2fec0576f963'))
 paddle.fluid.io.load_vars (ArgSpec(args=['executor', 'dirname', 'main_program', 'vars', 'predicate', 'filename'], varargs=None, keywords=None, defaults=(None, None, None, None)), ('document', '1bb9454cf09d71f190bb51550c5a3ac9'))
 paddle.fluid.io.load_params (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', '944291120d37bdb037a689d2c86d0a6e'))
 paddle.fluid.io.load_persistables (ArgSpec(args=['executor', 'dirname', 'main_program', 'filename'], varargs=None, keywords=None, defaults=(None, None)), ('document', '28df5bfe26ca7a077f91156abb0fe6d2'))
 paddle.fluid.io.save_inference_model (ArgSpec(args=['dirname', 'feeded_var_names', 'target_vars', 'executor', 'main_program', 'model_filename', 'params_filename', 'export_for_deployment', 'program_only'], varargs=None, keywords=None, defaults=(None, None, None, True, False)), ('document', 'fc82bfd137a9b1ab8ebd1651bd35b6e5'))
 paddle.fluid.io.load_inference_model (ArgSpec(args=['dirname', 'executor', 'model_filename', 'params_filename', 'pserver_endpoints'], varargs=None, keywords=None, defaults=(None, None, None)), ('document', '2f54d7c206b62f8c10f4f9d78c731cfd'))
 paddle.fluid.io.PyReader.__init__ (ArgSpec(args=['self', 'feed_list', 'capacity', 'use_double_buffer', 'iterable', 'return_list'], varargs=None, keywords=None, defaults=(None, None, True, True, False)), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
-paddle.fluid.io.PyReader.decorate_batch_generator (ArgSpec(args=['self', 'reader', 'places'], varargs=None, keywords=None, defaults=(None,)), ('document', '4a072de39998ee4e0de33fcec11325a6'))
-paddle.fluid.io.PyReader.decorate_sample_generator (ArgSpec(args=['self', 'sample_generator', 'batch_size', 'drop_last', 'places'], varargs=None, keywords=None, defaults=(True, None)), ('document', '3db4b24d33fe4f711e303f9673dc5c6a'))
-paddle.fluid.io.PyReader.decorate_sample_list_generator (ArgSpec(args=['self', 'reader', 'places'], varargs=None, keywords=None, defaults=(None,)), ('document', '94adc0fb71c4b2ae6c3c74886c9cb898'))
-paddle.fluid.io.PyReader.reset (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', 'd83714baf29f58d1605547e23d471fc7'))
-paddle.fluid.io.PyReader.start (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', 'ac8d2fd0a8581a01616c6458ef3c04cb'))
+paddle.fluid.io.PyReader.decorate_batch_generator (ArgSpec(args=['self', 'reader', 'places'], varargs=None, keywords=None, defaults=(None,)), ('document', '4364e836e3cb8ab5e68e411b763c50c7'))
+paddle.fluid.io.PyReader.decorate_sample_generator (ArgSpec(args=['self', 'sample_generator', 'batch_size', 'drop_last', 'places'], varargs=None, keywords=None, defaults=(True, None)), ('document', 'efa4c8b90fe6d99dcbda637b70351bb1'))
+paddle.fluid.io.PyReader.decorate_sample_list_generator (ArgSpec(args=['self', 'reader', 'places'], varargs=None, keywords=None, defaults=(None,)), ('document', '6c11980092720de304863de98074a64a'))
+paddle.fluid.io.PyReader.reset (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', '7432197701fdaab1848063860dc0b97e'))
+paddle.fluid.io.PyReader.start (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', 'f6395fd95b025000c5c7a5be31aebc4e'))
 paddle.fluid.initializer.ConstantInitializer.__init__ (ArgSpec(args=['self', 'value', 'force_cpu'], varargs=None, keywords=None, defaults=(0.0, False)), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
 paddle.fluid.initializer.UniformInitializer.__init__ (ArgSpec(args=['self', 'low', 'high', 'seed'], varargs=None, keywords=None, defaults=(-1.0, 1.0, 0)), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
 paddle.fluid.initializer.NormalInitializer.__init__ (ArgSpec(args=['self', 'loc', 'scale', 'seed'], varargs=None, keywords=None, defaults=(0.0, 1.0, 0)), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
@@ -248,7 +248,7 @@ paddle.fluid.layers.shuffle (ArgSpec(args=['reader', 'buffer_size'], varargs=Non
 paddle.fluid.layers.batch (ArgSpec(args=['reader', 'batch_size'], varargs=None, keywords=None, defaults=None), ('document', 'fcb24383c6eef2ca040ee824c26e22fd'))
 paddle.fluid.layers.double_buffer (ArgSpec(args=['reader', 'place', 'name'], varargs=None, keywords=None, defaults=(None, None)), ('document', 'c13b8a8521bea5f8123b925ae2a5d5db'))
 paddle.fluid.layers.random_data_generator (ArgSpec(args=['low', 'high', 'shapes', 'lod_levels', 'for_parallel'], varargs=None, keywords=None, defaults=(True,)), ('document', '9b7f0f86ec24bbc97643cadcb6499cff'))
-paddle.fluid.layers.py_reader (ArgSpec(args=['capacity', 'shapes', 'dtypes', 'lod_levels', 'name', 'use_double_buffer'], varargs=None, keywords=None, defaults=(None, None, True)), ('document', '0a77c56dff556b5ae4c5630d9a0764ef'))
+paddle.fluid.layers.py_reader (ArgSpec(args=['capacity', 'shapes', 'dtypes', 'lod_levels', 'name', 'use_double_buffer'], varargs=None, keywords=None, defaults=(None, None, True)), ('document', 'd78a1c7344955c5caed8dc13adb7beb6'))
 paddle.fluid.layers.create_py_reader_by_data (ArgSpec(args=['capacity', 'feed_list', 'name', 'use_double_buffer'], varargs=None, keywords=None, defaults=(None, True)), ('document', 'b42332b894e1e0962c6a43f0151c2640'))
 paddle.fluid.layers.Preprocessor.__init__ (ArgSpec(args=['self', 'reader', 'name'], varargs=None, keywords=None, defaults=(None,)), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))
 paddle.fluid.layers.Preprocessor.block (ArgSpec(args=['self'], varargs=None, keywords=None, defaults=None), ('document', '6adf97f83acf6453d4a6a4b1070f3754'))

python/paddle/fluid/io.py

@@ -264,6 +264,8 @@ def save_params(executor, dirname, main_program=None, filename=None):
     Examples:
         .. code-block:: python
 
+            import paddle.fluid as fluid
+
             exe = fluid.Executor(fluid.CPUPlace())
             param_path = "./my_paddle_model"
             prog = fluid.default_main_program()
@@ -487,6 +489,8 @@ def save_persistables(executor, dirname, main_program=None, filename=None):
     Examples:
         .. code-block:: python
 
+            import paddle.fluid as fluid
+
             exe = fluid.Executor(fluid.CPUPlace())
             param_path = "./my_paddle_model"
             # `prog` can be a program defined by the user

python/paddle/fluid/layers/io.py

@@ -709,11 +709,11 @@ def py_reader(capacity,
          exe = fluid.ParallelExecutor(use_cuda=True)
          for epoch_id in range(10):
              reader.start()
-                 try:
-                     while True:
-                         exe.run(fetch_list=[loss.name])
-                 except fluid.core.EOFException:
-                     reader.reset()
+             try:
+                 while True:
+                     exe.run(fetch_list=[loss.name])
+             except fluid.core.EOFException:
+                 reader.reset()
 
          fluid.io.save_inference_model(dirname='./model',
                                        feeded_var_names=[img.name, label.name],
@@ -748,8 +748,8 @@ def py_reader(capacity,
                                                        dtypes=['float32', 'int64'],
                                                        name='train_reader')
                  train_reader.decorate_paddle_reader(
-                 paddle.reader.shuffle(paddle.batch(mnist.train(), batch_size=5),
-                                       buf_size=500))
+                     paddle.reader.shuffle(paddle.batch(mnist.train(), batch_size=5),
+                                           buf_size=500))
                  train_loss = network(train_reader)  # some network definition
                  adam = fluid.optimizer.Adam(learning_rate=0.01)
                  adam.minimize(train_loss)
@@ -1148,6 +1148,8 @@ class Preprocessor(object):
     Examples:
           .. code-block:: python
 
+           import paddle.fluid as fluid
+
            reader = fluid.layers.io.open_files(
                filenames=['./data1.recordio', './data2.recordio'],
                shapes=[(3, 224, 224), (1, )],

python/paddle/fluid/reader.py

@@ -72,6 +72,10 @@ class PyReader(object):
 
         .. code-block:: python
 
+           import paddle
+           import paddle.fluid as fluid
+           import numpy as np
+
            EPOCH_NUM = 3
            ITER_NUM = 5
            BATCH_SIZE = 3
@@ -117,6 +121,10 @@ class PyReader(object):
 
         .. code-block:: python
 
+           import paddle
+           import paddle.fluid as fluid
+           import numpy as np
+
            EPOCH_NUM = 3
            ITER_NUM = 5
            BATCH_SIZE = 10
@@ -343,7 +351,11 @@ class PyReader(object):
         
 	Example:
 	    .. code-block:: python
-	
+
+                import paddle
+                import paddle.fluid as fluid
+                import numpy as np
+
                 BATCH_SIZE = 10
 
                 def generator():
@@ -379,6 +391,10 @@ class PyReader(object):
         Example:
             .. code-block:: python
 
+                import paddle
+                import paddle.fluid as fluid
+                import numpy as np
+
                 BATCH_SIZE = 10
 
                 def generator():
@@ -459,6 +475,9 @@ class PyReader(object):
         Example:
             .. code-block:: python
 
+                import paddle.fluid as fluid
+                import numpy as np
+
                 EPOCH_NUM = 3
                 ITER_NUM = 15
                 BATCH_SIZE = 3
@@ -539,6 +558,10 @@ class PyReader(object):
         Example:
             .. code-block:: python
 
+                import paddle
+                import paddle.fluid as fluid
+                import numpy as np
+
                 EPOCH_NUM = 3
                 ITER_NUM = 15
                 BATCH_SIZE = 3
@@ -609,6 +632,9 @@ class PyReader(object):
         Example:
             .. code-block:: python
 
+                import paddle.fluid as fluid
+                import numpy as np
+
                 EPOCH_NUM = 3
                 ITER_NUM = 15
                 BATCH_SIZE = 3