how to see if a work includes a letter in python code example

Example 1: python if string contains char

myString = "<text contains this>"
myOtherString = "AnotherString"

# Casting to string is not needed but it's good practice
# to check for errors 

if str(myString) in str(myOtherString): 
    # Do Something
else:
	# myOtherString didn't contain myString

Example 2: python check if string contains one of characters list

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