Recover the attributes of torch in memory_format_tutorial (#1112)

Co-authored-by: Brian Johnson <brianjo@fb.com>

Author: guyang3532

intermediate_source/memory_format_tutorial.py

@@ -261,14 +261,17 @@ def check_cl(*args, **kwargs):
         return result
     return check_cl
 
+old_attrs = dict()
 
 def attribute(m):
+    old_attrs[m] = dict()
     for i in dir(m):
         e = getattr(m, i)
         exclude_functions = ['is_cuda', 'has_names', 'numel',
                              'stride', 'Tensor', 'is_contiguous', '__class__']
         if i not in exclude_functions and not i.startswith('_') and '__call__' in dir(e):
             try:
+                old_attrs[m][i] = e
                 setattr(m, i, check_wrapper(e))
             except Exception as e:
                 print(i)
@@ -286,6 +289,13 @@ def attribute(m):
 # guide https://github.com/pytorch/pytorch/wiki/Writing-memory-format-aware-operators.
 #
 
+######################################################################
+# Code below is to recover the attributes of torch.
+
+for (m, attrs) in old_attrs.items():
+  for (k,v) in attrs.items():
+    setattr(m, k, v)
+
 ######################################################################
 # Work to do
 # ----------