Extracting and replacing a particular string from a sentence in python

Say I have a string,

s1="Hey Siri open call up duty"

and another string

s2="call up duty".

Now I know that "call up duty" should be replaced by "call of duty".

Say s3="call of duty".

So what I want to do is that from s1 delete s2 and place s3 in its location. I am not sure how this can be done. Can anyone please guide me as I am new to python. The answer should be

"Hey siri open call of duty"

Note--> s2 can be anywhere within the string s1 and need not be at the last everytime

In python, Strings have a replace() method which you can easily use to replace the sub-string s2 with s3.

s1 = "Hey Siri open call up duty"
s2 = "call up duty"
s3 =  "call of duty"

s1 = s1.replace(s2, s3)
print(s1)

This should do it for you. For more complex substitutions the re module can be of help.

You can use f string to use different string blocks in the string.

s2= "call up duty"
s3= "call of duty"
s1= f"Hey Siri open {s2}"