For example,
list1 = [ ['str1', 'str2', 'str3'],
[['str4', 'str5'], 'str6', 'str7', 'str8'],
['str9', 'str10']]
list1 = [ ['str1', 'str2', 'str3For example,
list1 = [ ['str1', 'str2', 'str3'],
[['str4', 'str5'], 'str6', 'str7', 'str8'],
['str9', 'str10']]
list1 = [ ['str1', 'str2', 'str3