Deny backslash using regex

[snippsat]

You have probably typed or copied that string yourself.
When it parsed or coming other placed from python it will be \\:

v_char = "search?q=\\"

This is because of escape character,so python read it as one \.
Will see this if use print().

>>> v_char = "search?q=\\"
>>> v_char 
'search?q=\\'
>>>
>>> print(v_char)
>>> search?q=\