def _fail_if_dependency_already_exists(self, dependency, consumer):
        if self._dependency_graph.has_edge(dependency, consumer):
            e_msg = 'Dependency relationship already exists.'
            detail = (dependency, consumer) % 'A dependency relationship from %r to %r already exists in this graph.'
            raise exceptions.AlreadyExistingDependency(e_msg, detail)
dataset/ETHPy150Open foundit/Piped/piped/dependencies.py/DependencyManager._fail_if_dependency_already_exists/swapped operands of `%`