T9 key combinations: If you enter the keys of REAL_TEST into a T9 keyboard, which other words would be valid under the same keystrokes?

keys.py

from functools import partial
from itertools import product

# pip install pyenchant
from enchant import Dict # I'm on Windows so I don't have a native dictionary sryyyy

REAL_TEST = 'selected' # rejected as expected, also selectee
REAL_WORDS = Dict('en_US')
LETTERTOKEY = {
    'abc': 2,
    'def': 3,
    'ghi': 4,
    'jkl': 5,
    'mno': 6,
    'pqrs': 7,
    'tuv': 8,
    'wxyz': 9,
}
KEYTOLETTER = {v: k for k, v in LETTERTOKEY.items()}


def find_key(letter):
    for key in LETTERTOKEY.keys():
        if letter in key:
            return LETTERTOKEY[key]

    return -1

def find_letter(key_input):
    for key in KEYTOLETTER.keys():
        if key == key_input:
            return KEYTOLETTER[key]

def explode(s):
    return list(s)

source = REAL_TEST
source_keys = list(map(find_key, REAL_TEST))
possible_letters = [explode(key_letters) for key_letters in map(find_letter, source_keys)] # list of all possible letters per key, as a list itself
combinations = product(*possible_letters)
for combination in combinations:
    comb_s = ''.join(combination)
    if REAL_WORDS.check(comb_s) and comb_s != source:
        print(comb_s)