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

Example Input: Sentence: 'a refrigerator with both its doors open in a kitchen'. Replace the letter 'o' with 'x' in the sentence.
Example Output: a refrigeratxr with bxth its dxxrs xpen in a kitchen

Example Input: Sentence: 'a couple of people that are petting a horse'. Replace the letter 'e' with 'p' in the sentence.
Example Output: a couplp of ppoplp that arp pptting a horsp

Example Input: Sentence: 'a hot dog packed with toppings sits in front of the bag from the hot dog shop'. Replace the letter 'g' with 'b' in the sentence.
Example Output:
a hot dob packed with toppinbs sits in front of the bab from the hot dob shop