diff --git a/edward/util/random_variables.py b/edward/util/random_variables.py
index 1a388ffdc..4a81e5fde 100644
--- a/edward/util/random_variables.py
+++ b/edward/util/random_variables.py
@@ -264,31 +264,28 @@ def copy(org_instance, dict_swap=None, scope="copied",
     else:
       new_original_op = None
 
-    # Make a copy of the node def.
-    # As an instance of tensorflow.core.framework.graph_pb2.NodeDef, it
-    # stores string-based info such as name, device, and type of the op.
-    # It is unique to every Operation instance.
+    # Copy the node def.
     new_node_def = deepcopy(op.node_def)
     new_node_def.name = new_name
 
     # Copy the other inputs needed for initialization.
     output_types = op._output_types[:]
 
-    # Make a copy of the op def.
+    # Copy the op def.
     # It is unique to every Operation type.
     op_def = deepcopy(op.op_def)
 
-    ret = tf.Operation(new_node_def,
-                       graph,
-                       [],
-                       output_types,
-                       [],
-                       [],
-                       new_original_op,
-                       op_def)
+    new_op = tf.Operation(new_node_def,
+                          graph,
+                          [],
+                          output_types,
+                          [],
+                          [],
+                          new_original_op,
+                          op_def)
 
     # advertise op early to break recursions
-    graph._add_op(ret)
+    graph._add_op(new_op)
 
     # If it has control inputs, copy them.
     elems = []
@@ -299,7 +296,7 @@ def copy(org_instance, dict_swap=None, scope="copied",
 
       elems.append(elem)
 
-    ret._add_control_inputs(elems)
+    new_op._add_control_inputs(elems)
 
     # If it has inputs, copy them.
     for x in op.inputs:
@@ -307,7 +304,7 @@ def copy(org_instance, dict_swap=None, scope="copied",
       if not isinstance(elem, tf.Operation):
         elem = tf.convert_to_tensor(elem)
 
-      ret._add_input(elem)
+      new_op._add_input(elem)
 
     # Use Graph's private methods to add the op, following
     # implementation of `tf.Graph().create_op()`.
@@ -316,11 +313,11 @@ def copy(org_instance, dict_swap=None, scope="copied",
     op_type = new_name
 
     if compute_shapes:
-      set_shapes_for_outputs(ret)
-    graph._record_op_seen_by_control_dependencies(ret)
+      set_shapes_for_outputs(new_op)
+    graph._record_op_seen_by_control_dependencies(new_op)
 
     if compute_device:
-      graph._apply_device_functions(ret)
+      graph._apply_device_functions(new_op)
 
     if graph._colocation_stack:
       all_colocation_groups = []
@@ -330,17 +327,17 @@ def copy(org_instance, dict_swap=None, scope="copied",
           # Make this device match the device of the colocated op, to
           # provide consistency between the device and the colocation
           # property.
-          if ret.device and ret.device != colocation_op.device:
+          if new_op.device and new_op.device != colocation_op.device:
             logging.warning("Tried to colocate %s with an op %s that had "
                             "a different device: %s vs %s. "
                             "Ignoring colocation property.",
-                            name, colocation_op.name, ret.device,
+                            name, colocation_op.name, new_op.device,
                             colocation_op.device)
           else:
-            ret._set_device(colocation_op.device)
+            new_op._set_device(colocation_op.device)
 
       all_colocation_groups = sorted(set(all_colocation_groups))
-      ret.node_def.attr["_class"].CopyFrom(attr_value_pb2.AttrValue(
+      new_op.node_def.attr["_class"].CopyFrom(attr_value_pb2.AttrValue(
           list=attr_value_pb2.AttrValue.ListValue(s=all_colocation_groups)))
 
     # Sets "container" attribute if
@@ -351,12 +348,12 @@ def copy(org_instance, dict_swap=None, scope="copied",
     if (graph._container and
         op_type in graph._registered_ops and
         graph._registered_ops[op_type].is_stateful and
-        "container" in ret.node_def.attr and
-            not ret.node_def.attr["container"].s):
-      ret.node_def.attr["container"].CopyFrom(
+        "container" in new_op.node_def.attr and
+            not new_op.node_def.attr["container"].s):
+      new_op.node_def.attr["container"].CopyFrom(
           attr_value_pb2.AttrValue(s=compat.as_bytes(graph._container)))
 
-    return ret
+    return new_op
   else:
     raise TypeError("Could not copy instance: " + str(org_instance))