grammar optimized.

python/paddle/fluid/io.py

@@ -492,7 +492,7 @@ def save_checkpoint(executor,
     if not os.path.isdir(checkpoint_dir):
         os.makedirs(checkpoint_dir)
 
-    serial = _get_lastest_checkpoint_dir(checkpoint_dir) + 1
+    serial = _get_latest_checkpoint_dir(checkpoint_dir) + 1
     cur_dir = _get_serial_dir(checkpoint_dir, serial)
 
     save_trainer_args(cur_dir, trainer_id, trainer_args)
@@ -505,11 +505,11 @@ def save_checkpoint(executor,
 
 def get_latest_checkpoint_serial(checkpoint_dir):
     """
-    If the directory have checkpoint files, it will return lastest checkpoint directory serial number
+    If the directory have checkpoint files, it will return latest checkpoint directory serial number
 
     :param checkpoint_dir
     """
-    serial = _get_lastest_checkpoint_dir(checkpoint_dir)
+    serial = _get_latest_checkpoint_dir(checkpoint_dir)
     if serial < 0:
         return None
     return serial
@@ -639,14 +639,14 @@ def _is_checkpoint_var(var):
             var.desc.type() == core.VarDesc.VarType.FETCH_LIST or \
             var.desc.type() == core.VarDesc.VarType.RAW:
         return False
-    # @GRAD are named for gradient varibales, checkpoint will not save it.
+    # @GRAD are named for gradient variables, checkpoint will not save it.
     if "@GRAD" in var.name:
         return False
-    # .trainer_ are named for distribute trian variables, checkpoint will not save it.
+    # .trainer_ are named for distribute train variables, checkpoint will not save it.
     if ".trainer_" in var.name:
         return False
 
-    # .block is named for distribute trian variables, checkpoint will not save it.
+    # .block is named for distribute train variables, checkpoint will not save it.
     if ".block" in var.name:
         return False
 
@@ -656,7 +656,6 @@ def _is_checkpoint_var(var):
 def _get_dir_serial(dirname):
     _, serial = dirname.split(CHECKPOINT_SEPARATOR)
 
-    serial_num = -1
     try:
         serial_num = int(serial)
     except ValueError:
@@ -723,7 +722,7 @@ def _write_success(dirname):
         f.write(now)
 
 
-def _get_lastest_checkpoint_dir(checkpoint_dir):
+def _get_latest_checkpoint_dir(checkpoint_dir):
     """
     get the latest file in checkpoint directory, the _SUCCESS file must exist in the directory