Decorate a class to be persistent, utilizing pyyaml as serializer

persistent.py

import yaml


def persistent(K):
    def __repr__(self):
        i_vars = dict([(k,self.__dict__[k]) for k in self.__dict__ if not k.startswith('__') and not callable(self.__dict__[k])])
        s = "<" + K.__name__ + '('
        keywords = []
        for i_var in i_vars:
           keywords.append("%s=%s" % (i_var,repr(i_vars[i_var])))
        s += ','.join(keywords)
        s += ')>'
        return s
    if not hasattr(K,'__repr__'):
        K.__repr__ = __repr__
        K.__str__ = __repr__

    def get_yaml(self):
        yamlDict = dict([(k,self.__dict__[k]) for k in self.__dict__ if not k.startswith('__') and not callable(self.__dict__[k])])
        yamlText = yaml.dump(yamlDict, default_flow_style=False)
        return yamlText
    if not hasattr(K,'get_yaml'):
       K.get_yaml = get_yaml
    def save_yaml(self):
       yamlText = self.get_yaml()
       if hasattr(self,"name"):
          filePath = "%s_%s.yaml" % (self.__class__.__name__,self.name)
       else:
          filePath = "%s_%d.yaml" % (self.__class__.__name__, self.__hash__())
       with open(filePath, 'w') as yamlFile:
            yamlFile.write(yamlText)
    K.save_yaml = save_yaml
    @classmethod
    def load_from_file(cls,filePath):
        with open(filePath, 'r') as yamlFile:
            try:
                yamlDict = yaml.load(yamlFile)
                return K(**yamlDict)
            except Exception, e:
                raise
    if not hasattr(K,'load_from_file'):
        K.load_from_file = load_from_file
    return K