Please answer with your own work and handle the question by python. please also check if the program is executable. Thank you. Please use the given program for part c.

given program of 2c:

def letter_to_number(letter): alphabet={\"a\":0,\"b\":1,\"c\":2,\"d\":3,\"e\":4,\"f\":5,\"g\":6,\"h\":7,\"i\":8,\"j\":9,\"k\":10,\"l\":11,\"m\":12,\"n\":13, \"o\":14,\"p\":15,\"q\":16,\"r\":17,\"s\":18,\"t\":19,\"u\":20,\"v\":21,\"w\":22,\"x\":23,\"y\":24,\"z\":25} return alphabet.get(letter)

def number_to_letter(number): numbers={0:\"a\",1:\"b\",2:\"c\",3:\"d\",4:\"e\",5:\"f\",6:\"g\",7:\"h\",8:\"i\",9:\"j\",10:\"k\",11:\"l\",12:\"m\",13:\"n\", 14:\"o\",15:\"p\",16:\"q\",17:\"r\",18:\"s\",19:\"t\",20:\"u\",21:\"v\",22:\"w\",23:\"x\",24:\"y\",25:\"z\"} return numbers.get(number)