update merge_selected_rows

Author: Shixiaowei02

python/paddle/fluid/layers/control_flow.py

@@ -941,9 +941,6 @@ def less_than(x, y, force_cpu=None, cond=None):
     """
     ${comment}
 
-    >>> import paddle.fluid as fluid
-    >>> less = fluid.layers.less_than(x=label, y=limit)
-
     Args:
         x(${x_type}): ${x_comment}.
         y(${y_type}): ${y_comment}.
@@ -955,6 +952,7 @@ def less_than(x, y, force_cpu=None, cond=None):
 
     Examples:
         .. code-block:: python
+
           out = fluid.layers.less_than(x=label, y=limit)
     """
     helper = LayerHelper("less_than", **locals())

python/paddle/fluid/layers/nn.py

@@ -9825,9 +9825,11 @@ def merge_selected_rows(x, name=None):
     Examples:
         .. code-block:: python
 
-            input = fluid.layers.data(
-                name='data', shape=[2, 3], dtype='float32')
-            mean = fluid.layers.mean(input)
+            b = fluid.default_main_program().global_block()
+            var = b.create_var(
+                name="X", dtype="float32", persistable=True,
+                type=fluid.core.VarDesc.VarType.SELECTED_ROWS)
+            y = fluid.layers.merge_selected_rows(var)
     """
 
     helper = LayerHelper("merge_selected_rows", **locals())