How to set a python property in __init__

class STransaction(object):
    """A statement transaction"""
    def __init__(self, date):
        self._date = None #1
        self.date = date  #2

If you want to set the proxy field self._date without executing of your setter use the #1 line. If you would like to execute the setter at startup too use the #2. Both ways are correct, it's just a matter of what do you want to do.

I do not see any real problem with your code. In __init__, the class is fully created and thus the properties accessible.