Two ways…

OneUndo decorater by Cesar Saez

from functools import wraps  
    
def OneUndo(function):  
   @wraps(function)  
   def _inner(*args, **kwargs):  
     try:  
       Application.BeginUndo()  
       f = function(*args, **kwargs)  
     finally:  
       Application.EndUndo()  
       return f  
   return _inner
#
# And a basic example...
# 
@OneUndo 
def CreateNulls(p_iCounter=100):
     lNulls = []
     for i in range(p_iCounter):
       lNulls.append( Application.ActiveSceneRoot.AddNull() )
     return lNulls

CreateNulls()

Undo with statement by ethivierge

from win32com.client import constants as c
from win32com.client.dynamic import Dispatch as d
 
xsi = Application
log = xsi.LogMessage
collSel = xsi.Selection
 
 
class xsiUndo():
    def __enter__(self):
        xsi.BeginUndo()
 
    def __exit__(self, type, value, traceback):
        xsi.EndUndo()
 
 
def testFunc():
    log("running test")
 
 
with xsiUndo():
    testFunc()