check if string contains only one character python code example

Example 1: python check if string contains one of characters list

if any(ext in url_string for ext in extensionsToCheck):
    print(url_string)

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")