def frequencies(fname):
    with open(fname) as f:
        text = f.read()
    freq = {}
    for char in text:
        if char.isalpha():  # Consider only alphabetic characters
            char = char.lower()  # Normalize to lowercase
            if char in freq:
                freq[char] += 1
            else:
                freq[char] = 1
    keys = sorted(freq)
    
    sorted_freq = {}
    for key in keys:
        sorted_freq[key] = freq[key]
    return sorted_freq


frequencies("data.txt")  

{'a': 319,
 'b': 44,
 'c': 134,
 'd': 117,
 'e': 443,
 'f': 68,
 'g': 68,
 'h': 85,
 'i': 175,
 'j': 4,
 'k': 20,
 'l': 172,
 'm': 91,
 'n': 140,
 'o': 305,
 'p': 102,
 'q': 21,
 'r': 221,
 's': 365,
 't': 272,
 'u': 124,
 'v': 40,
 'w': 42,
 'x': 1,
 'y': 49,
 'z': 6}

xs = [5,3,4,9,1]
ys = sorted(xs)
print(xs,ys)

[5, 3, 4, 9, 1] [1, 3, 4, 5, 9]

xs = [5,3,4,9,1]
ys = xs.sort()
print(xs,ys)

[1, 3, 4, 5, 9] None

char = 'A'
c = char.lower()
print(char,c)

A False