import re
str = """useless stuff
fruit: apple
fruit: banana
useless stuff
fruit: kiwi
fruit: orange
fruit: pear
useless stuff"""
print re.findall(r'fruit: ([\w]+)\n|[^\n]*\n', str, re.M);
aW1wb3J0IHJlCnN0ciA9ICIiInVzZWxlc3Mgc3R1ZmYKIApmcnVpdDogYXBwbGUKZnJ1aXQ6IGJhbmFuYQogCnVzZWxlc3Mgc3R1ZmYKIApmcnVpdDoga2l3aQpmcnVpdDogb3JhbmdlCmZydWl0OiBwZWFyCiAKdXNlbGVzcyBzdHVmZiIiIgpwcmludCByZS5maW5kYWxsKHInZnJ1aXQ6IChbXHddKylcbnxbXlxuXSpcbicsIHN0ciwgcmUuTSk7
['', '', 'apple', 'banana', '', '', '', 'kiwi', 'orange', 'pear', '']