1def beginning(word):
 2    '''Derive the beginning of a word, keeping in mind the remainder of the division of the word`s length by 3.'''
 3    length = len(word)
 4    if length % 3 == 0:
 5        return word[0:length // 3]
 6    elif length % 3 == 1:
 7        return word[0:length // 3]
 8    else:
 9        return word[0:length // 3 + 1]
10
11def middle(word):
12    '''Derive the middle of a word, keeping in mind the remainder of the division of the word`s length by 3.'''
13    length = len(word)
14    if length % 3 == 0:
15        return word[length // 3:2 * (length // 3)]
16    elif length % 3 == 1:
17        return word[length // 3:2 * (length // 3) + 1]
18    else:
19        return word[length // 3 + 1:2 * (length // 3) + 1]
20
21def end(word):
22    '''Derive the end of a word, keeping in mind the remainder of the division of the word`s length by 3.'''
23    length = len(word)
24    if length % 3 == 0:
25        return word[2 * (length // 3):length]
26    elif length % 3 == 1:
27        return word[2 * (length // 3) + 1:length]
28    else:
29        return word[2 * (length // 3) + 1:length]
30
31def split_sentence(sentence):
32    '''Turn a string into a list of tuples, taking into account the rules that have been implemented in the first three functions.'''
33    words_list = sentence.split()
34    result = []
35    for word in words_list:
36        result.append((beginning(word), middle(word), end(word)))
37    return result