code: def plot(self,**kwargs):
          
          #
          if "ax" in kwargs:
              ax = kwargs.pop("ax")
          else:
              try:
                  import matplotlib.pyplot as plt
              except Exception as e:
                  raise Exception("error importing matplotlib: {0}".format(str(e)))
  
              ax = plt.subplot(111)
          legend = kwargs.pop("legend",False)
          individuals = kwargs.pop("individuals",False)
          xmx = max([v.a*3.0 for v in self.variograms])
          x = np.linspace(0,xmx,100)
          y = np.zeros_like(x)
          for v in self.variograms:
              yv = v.inv_h(x)
              if individuals:
                  ax.plot(x,yv,label=v.name,**kwargs)
              y += yv
          y += self.nugget
          ax.plot(x,y,label=self.name,**kwargs)
          if legend:
              ax.legend()
          ax.set_xlabel("distance")
          ax.set_ylabel("$\gamma$")
          return ax
docs: make a cheap plot of the GeoStruct
  
          Parameters
          ----------
          **kwargs : (dict)
              keyword arguments to use for plotting.
  
          Returns
          -------
          ax : matplotlib.pyplot.axis
              the axis with the GeoStruct plot
  
          Note
          ----
          optional arguments include "ax" (an existing axis),
          "individuals" (plot each variogram on a separate axis),
          "legend" (add a legend to the plot(s)).  All other kwargs
          are passed to matplotlib.pyplot.plot()