In this task, you need to replace a letter in the sentence with another given letter.

Example Input: Sentence: 'there is a purse on the floor with its contents spilled out'. Replace the letter 'd' with 'v' in the sentence.
Example Output: there is a purse on the floor with its contents spillev out

Example Input: Sentence: 'a tennis racket is sitting in the middle of a tennis field'. Replace the letter 'i' with 'f' in the sentence.
Example Output: a tennfs racket fs sfttfng fn the mfddle of a tennfs ffeld

Example Input: Sentence: 'a man holds an owl in front of a forest'. Replace the letter 'f' with 'v' in the sentence.
Example Output:
a man holds an owl in vront ov a vorest