Your task is to implement a function replace_once(t, d), that takes a text t and a replacement dictionary d, and returns the result of replacing words according to the dictionary: if a word appears as a key, replace it with the dictionary value, and if a word does not appear in the dictionary, leave it alone. Given a list of words, you can concatenate them together with spaces in between as follows:
word_list = "I love eating bananas".split()
print("Word list:", word_list)
back_together = " ".join(word_list)
print("Back together:", back_together)
# You can also join them in other ways, btw. Just DON'T do it for this homework.
print("You can also put commas:", ", ".join(word_list))