import re
a = '''big mouse eats cheese? "non-detected string" 'non-detected string too' hello guys'''
print( [x for x in re.findall(r'''"[^"]*"|'[^']*'|\b([^\d\W]+)\b''', a) if x])
aW1wb3J0IHJlCmEgPSAnJydiaWcgbW91c2UgZWF0cyBjaGVlc2U/ICJub24tZGV0ZWN0ZWQgc3RyaW5nIiAnbm9uLWRldGVjdGVkIHN0cmluZyB0b28nIGhlbGxvIGd1eXMnJycKcHJpbnQoIFt4IGZvciB4IGluIHJlLmZpbmRhbGwocicnJyJbXiJdKiJ8J1teJ10qJ3xcYihbXlxkXFddKylcYicnJywgYSkgaWYgeF0p