class vs static

Good explanation of classmethod vs staticmethod.

http://stackoverflow.com/questions/12179271/python-classmethod-and-staticmethod-for-beginner
http://stackoverflow.com/questions/735975/static-methods-in-python

class Date(object):

    day = 0
    month = 0
    year = 0

    def __init__(self, day=0, month=0, year=0):
        self.day = day
        self.month = month
        self.year = year
        
    @classmethod
    def from_string(cls, date_as_string):
        day, month, year = map(int, date_as_string.split('-'))
        date1 = cls(day, month, year)
        return date1
        
    @staticmethod
    def is_date_valid(date_as_string):
        day, month, year = map(int, date_as_string.split('-'))
        return day <= 31 and month <= 12 and year <= 3999
        
So, as we can see from usage of staticmethod, we don't have any access to what the class is- it's basically just a 
function, called syntactically like a method, but without access to the object and it's internals (fields and another 
methods), while classmethod does.        

date2 = Date.from_string('11-09-2012')