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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def get_onnx_variable_name(self, seed):
        '''
        Retrieve the variable ID of the given seed or create one if it is the first time of seeing this seed
        '''
        if seed in self.variable_name_mapping:
            return self.variable_name_mapping[seed][-1]
        else:
            return self.get_unique_variable_name(seed)