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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 find_sink_variables(self):
        '''
        Find sink variables in this scope
        '''
        # First we assume all variables are sinks
        is_sink = {name: True for name in self.variables.keys()}
        # Then, we remove those variables which are inputs of some operators
        for operator in self.operators.values():
            for variable in operator.inputs:
                is_sink[variable.onnx_name] = False
        return [variable for name, variable in self.variables.items() if is_sink[name]]