import re

data = [
    "name['toronto'] = 'One'",
    "state['ontario'] = 'Two'",
    "country['canada']['ca'] = 'Three'",
    "extra['maple'] = 'Four'"
]

REGEX = re.compile(r"\['(?P<word>.*?)'\]")

for line in data:
    found = REGEX.search(line)
    if found:
        print(found.group('word'))

toronto
ontario
canada
maple