>>> replace each letter in 'ABCDEFGHIJKL' with the corresponding NATO Phonetic alphabet code

- elapsed 3.235 seconds -
nato_alphabet = {'A': 'Alfa', 'B': 'Bravo', 'C': 'Charlie', 'D': 'Delta',
    'E': 'Echo', 'F': 'Foxtrot', 'G': 'Golf', 'H': 'Hotel', 'I': 'India',
    'J': 'Juliett', 'K': 'Kilo', 'L': 'Lima', 'M': 'Mike', 'N': 'November',
    'O': 'Oscar', 'P': 'Papa', 'Q': 'Quebec', 'R': 'Romeo', 'S': 'Sierra',
    'T': 'Tango', 'U': 'Uniform', 'V': 'Victor', 'W': 'Whiskey', 'X':
    'Xray', 'Y': 'Yankee', 'Z': 'Zulu'}
alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
new_str = ''
for letter in message:
    if letter in alphabet:
        new_str += nato_alphabet[letter]
else:
    new_str += letter
print(new_str)