Port dist_transpiler to Python3.5

Resume prelu_op_test in python2

python/paddle/fluid/tests/unittests/test_prelu_op.py

@@ -16,6 +16,7 @@ from __future__ import print_function
 
 import unittest
 import numpy as np
+import six
 from op_test import OpTest
 
 
@@ -62,17 +63,20 @@ class PReluTest(OpTest):
 
 
 # TODO(minqiyang): Resume these test cases after fixing Python3 CI job issues
-#  class TestCase1(PReluTest):
-#  def initTestCase(self):
-#  self.attrs = {'mode': "all"}
+if six.PY2:
 
-#  class TestCase2(PReluTest):
-#  def initTestCase(self):
-#  self.attrs = {'mode': "channel"}
+    class TestCase1(PReluTest):
+        def initTestCase(self):
+            self.attrs = {'mode': "all"}
+
+    class TestCase2(PReluTest):
+        def initTestCase(self):
+            self.attrs = {'mode': "channel"}
+
+    class TestCase3(PReluTest):
+        def initTestCase(self):
+            self.attrs = {'mode': "element"}
 
-#  class TestCase3(PReluTest):
-#  def initTestCase(self):
-#  self.attrs = {'mode': "element"}
 
 if __name__ == "__main__":
     unittest.main()

python/paddle/fluid/transpiler/details/program_utils.py

@@ -153,7 +153,7 @@ def block_to_code(block, block_idx):
 
     indent += 1
     # sort all vars
-    all_vars = sorted(block.vars.iteritems(), key=lambda x: x[0])
+    all_vars = sorted(six.iteritems(block.vars), key=lambda x: x[0])
     for var in all_vars:
         print("{}{}".format(get_indent_space(indent), variable_to_code(var[1])))
 

python/paddle/fluid/transpiler/distribute_transpiler.py

@@ -300,7 +300,7 @@ class DistributeTranspiler(object):
             input_deps = grad_name_to_send_dummy_out.values()
             program.global_block().append_op(
                 type="send_barrier",
-                inputs={"X": input_deps},
+                inputs={"X": list(input_deps)},
                 outputs={"Out": send_barrier_out},
                 attrs={
                     "endpoints": pserver_endpoints,
@@ -455,7 +455,7 @@ class DistributeTranspiler(object):
             if len(splited_var) <= 1:
                 continue
             # NOTE: if enable memory optimization, origin vars maybe removed.
-            if startup_program.global_block().vars.has_key(varname):
+            if varname in startup_program.global_block().vars:
                 orig_param = startup_program.global_block().vars[varname]
             else:
                 origin_param_var = self.origin_program.global_block().vars[