Python entropy calculation of trigrams

Question

With this code in Python, I calculate the entropy value of a txt file based on trigrams, but something goes wrong, because the output value is 110.51908986855025 (which is way too high considering that the maximum entropy value of a file is 8 bits based on a logarithmic base of 2). Does anybody can find the mistake (or mistakes)?

import math

file = open("C:/Users/Mik/Documents/import pandas as pd.txt", "r")
content = file.read()

def generate_trigrams(string):
    trigrams = []
    for i in range(len(string) - 2):
        trigram = string[i:i + 3]
        trigrams.append(trigram)
    return trigrams

trigrams_content = generate_trigrams(content)
n_trigrams = len(trigrams_content)
print(n_trigrams)

def entropy(trigrams_content):
    trigram_freqs = {}
    for trigram in trigrams_content:
        if trigram in trigram_freqs:
            trigram_freqs[trigram] += 1
        else:
            trigram_freqs[trigram] = 1

    probs = [trigram_freqs[trigram] / len(trigrams_content) for trigram in trigrams_content]

    entropy = 0
    for prob in probs:
        entropy -= prob * math.log2(prob)

    return entropy

print(entropy(trigrams_content))