Python has a built-in function that can be called on a string object to replace all occurrences of a substring with a new substring. You can also optionally pass in the count argument, which controls the number of occurrences to replace.
message = "Hi, I'm a Python Expert!"
new_message = message.replace("Python", "Ruby")
print(new_message)
# Hi, I'm a Ruby Expert!message = "Where can you find what you need to finish the project that you just started."
# count is 2, so first 2 occurrences will be replaced
new_message = message.replace("you", "I", 2)
print(new_message)
# Where can I find what I need to finish the project that you just started.