Design Pattern for accessing subclass attributes

[UGuntupalli]

All,
I am looking for guidance on what would be good design pattern to use / implement given a particular problem.

Problem Statement:
Let us say we would like to define a class that defines i-phone. Please note the below example is only for illustration.
If a user of this class wants to determine the mfg.year which is only set in the sub-class, what is the best way to get that information, without knowing which sub-class to call.
The user is always only going to instantiate the base class that is of the IPhone().

class IPhone(): 
    def __init__(self,ver): 
        self.ver = ver
        self.phone_factory() 
    
    def phone_factory(self): 
        if self.ver == '3G':
            return IPhone3G()
        elif self.ver == '3GS': 
            return IPhone3GS() 
        elif self.ver == '4': 
            return IPhone4()
        elif self.ver == '4s': 
            return IPhone4s()
        elif self.ver == '5': 
            return IPhone5() 
        else: 
            pass 
        
class IPhone3G(): 
    def __init__(self): 
        self.year = 2007 

class IPhone3GS(): 
    def __init__(self): 
        self.year = 2009 

class IPhone4(): 
    def __init__(self): 
        self.year = 2010
    
class IPhone4s(): 
    def __init__(self): 
        self.year = 2011

class IPhone5(): 
    def __init__(self): 
        self.year = 2012

Potential Solution:
One way I can think of addressing this problem is by doing the following:

class IPhone(): 
    def __init__(self,ver): 
        self.ver = ver
        self.phone_factory() 
    
    def phone_factory(self): 
        if self.ver == '3G':
            t = IPhone3G()
            self.year = t.year
        elif self.ver == '3GS': 
            t = IPhone3GS() 
            self.year = t.year
        elif self.ver == '4': 
            t = IPhone4()
            self.year = t.year
        elif self.ver == '4s': 
            t = IPhone4s()
            self.year = t.year
        elif self.ver == '5': 
            t = IPhone5() 
            self.year = t.year
        else: 
            pass 
        
class IPhone3G(): 
    def __init__(self): 
        self.year = 2007 

class IPhone3GS(): 
    def __init__(self): 
        self.year = 2009 

class IPhone4(): 
    def __init__(self): 
        self.year = 2010
    
class IPhone4s(): 
    def __init__(self): 
        self.year = 2011

class IPhone5(): 
    def __init__(self): 
        self.year = 2012

But, is this a good approach ? I have looked at class methods and static methods as alternative options but I am not really sure what is the best approach. Can anybody advice?