def METHOD_NAME(self, a, b):
    """Draw an arrow from node a to node b
    Parameters
    ----------
    a: `oemof.solph.network.Node`
        An oemof node (usually a Bus or a Component)
    b: `oemof.solph.network.Node`
        An oemof node (usually a Bus or a Component)
    """
    a_label = linebreaks(str(a.label))
    b_label = linebreaks(str(b.label))
    if isinstance(b, HeatPipeline):
        self.dot.edge(a_label, "dh-network")
    elif isinstance(a, HeatPipeline):
        self.dot.edge("dh-network", b_label)
    elif isinstance(a, HeatPipeline) and isinstance(b, HeatPipeline):
        pass
    else:
        self.dot.edge(a_label, b_label)