Strip computation graph off annotations

strip.py

seen = set()                                        
def strip(obj):                                     
    if id(obj) in seen:                             
        return                                      
    seen.add(id(obj))                               
    if isinstance(obj, theano.Variable):            
        obj.tag.annotations = []                    
        obj.tag.roles = []                          
    if isinstance(obj, (list, tuple, set)):         
        for el in obj:                              
            strip(el)                               
    if isinstance(obj, dict):                       
        for key, value in obj.items():              
            strip(key)                              
            strip(value)                            
    if hasattr(obj, '__dict__'):                    
        for attr, value in obj.__dict__.items():    
            if not attr.startswith('_'):            
                strip(value)