here is an example letter set

d =[("e", "f"),

("e", "f"),

("e", "c"),

("f", "c"),

("f", "e")]

Use python to write a function called letters_to_dict that converts the letters set into a dictionary.

There is a single key for each character, The value corresponding to each key is a list of the characters.

example output {"e" : ["f", "f", "c"], "f" : ["e", "c"]}

Please use pyton and with clear explanation, thanks!