There's error when checking the custom_end input in backend.

[ksh168]

• There's error when checking the custom_end input in backend.

• This code should give error if custom_end contains characters which are not allowed.

#these two lines are causing error in backend
#purpose of these lines is to check input in custom_end
if((custom_end is not None) and (not re.search(regex, custom_end))):
    return "custom_url contains invalid characters", 400
#end input validation

• line 61 onwards in "routes.py" file
• But if custom_end is empty then also it gives error
• I initially thought (custom_end is not None) will be enough