file_name = 'my_file.txt'
my_list = []
prev_line = ''
with open(file_name, 'r') as file:
    for line in file:
        if prev_line != line:
            my_list = [line]
        else:
            my_list.append(line)
        print(my_list)
        prev_line = line

 my_lst = []
rep_lst = []
with open('my_file.txt', 'r') as f:
    for line in f.readlines():
        l = line.strip()
        if rep_lst:
            if rep_lst[-1] == l:
                rep_lst.append(l)
            else:
                if len(rep_lst) > 1:
                    my_lst.append(rep_lst)
                    rep_lst = [l]
                else:
                    rep_lst = [l]
        else:
            rep_lst.append(l)
    if len(rep_lst) > 1:
        my_lst.append(rep_lst)
print('______________________')
print(my_lst)

[['some_text', 'some_text', 'some_text'], ['other_text', 'other_text', 'other_text'], ['another_text', 'another_text', 'another_text']]

  
>>> file_name = 'my_file.txt'
>>> my_list = []
>>> prev_line = ''
>>> with open(file_name, 'r') as file:
...     for line in file:
...         if prev_line != line:
...             my_list.append([line])
...         else:
...             my_list[-1].append(line)
...         prev_line = line
...     print(my_list)
... 
[['some_text\n', 'some_text\n', 'some_text\n'], ['other_text\n', 'other_text\n', 'other_text\n'], ['another_text\n', 'another_text\n', 'another_text\n']]
>>>