class Trace:
    def __init__(self, descrStr):
        self.descr = descrStr
        self.x = None
        self.xlabel = None
        self.xunit = None
        self.y = None
        self.ylabel = None
        self.yunit = None

    def plot(self):
        import matplotlib.pyplot as plt
        plt.plot(self.x, self.y, label=self.descr)
        plt.legend()