Bang should be after the assignment operator

docs/source/interactive/python-ipython-diff.rst

@@ -185,7 +185,7 b' This allow you for example to put the list of files of the current working direc'
 
 .. code-block:: ipython
 
-    In[1]: my_files != ls
+    In[1]: my_files =! ls
 
 
 You can combine the different possibilities in for loops, condition, functions...: