check if a string does not contain a substring python code example

Example 1: if substring not in string python

fullstring = "StackAbuse"
substring = "tack"

if fullstring.find(substring) != -1:
    print "Found!"
else:
    print "Not found!"

Example 2: python check if string contains substring

string = "My favourite programming language is Python"
substring = "Python"

if substring in string:
    print("Python is my favorite language")
elif substring not in string:
    print("Python is not my favourite language")