[python/en] Fix @wraps decorator example (#5353)

The `__code__` example doesn't work as described but the `__doc__` does so I added a docstring and replaced the use of `__code__` with `__doc__`.

python.md

@@ -1061,6 +1061,7 @@ def log_function(func):
 
 @log_function               # equivalent:
 def my_function(x,y):       # def my_function(x,y):
+    """Adds two numbers together."""
     return x+y              #   return x+y
                             # my_function = log_function(my_function)
 # The decorator @log_function tells us as we begin reading the function definition
@@ -1076,7 +1077,7 @@ my_function(1,2)  # => "Entering function my_function"
 # What happens if we try to get some information about my_function?
 
 print(my_function.__name__)  # => 'wrapper'
-print(my_function.__code__.co_argcount)  # => 0. The argcount is 0 because both arguments in wrapper()'s signature are optional.
+print(my_function.__doc__)  # => None (wrapper function has no docstring)
 
 # Because our decorator is equivalent to my_function = log_function(my_function)
 # we've replaced information about my_function with information from wrapper
@@ -1097,6 +1098,7 @@ def log_function(func):
 
 @log_function
 def my_function(x,y):
+    """Adds two numbers together."""
     return x+y
 
 my_function(1,2)  # => "Entering function my_function"
@@ -1104,7 +1106,7 @@ my_function(1,2)  # => "Entering function my_function"
                   # => "Exiting function my_function"
 
 print(my_function.__name__)  # => 'my_function'
-print(my_function.__code__.co_argcount)  # => 2
+print(my_function.__doc__)  # => 'Adds two numbers together.'
 ```
 
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