>>> temp='Issac Asimov'
>>>
>>> for key in re.findall('Issac (?!Asimov)', temp):
...   print key
...
>>> for key in re.findall('Issac (?=Asimov)', temp):
...   print key
...
Issac
>>>
>>> for key in re.findall('(?!s )%\((.*?)\)d', MULTI):
...   print key
...
name)s %(year
month
day
>>> for key in re.findall('(?!s)%\((.*?)\)d', MULTI):
...   print key
...
name)s %(year
month
day
>>>
>>> for key in re.findall('(?!.*s)%\((.*?)\)d', MULTI):
...   print key
...
year
month
day