python check if string contains a subset of letters code example

Example 1: how to check if a string contains a word python

if word in mystring: 
   print('success')

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")