docs: def plot_xtime(self, y, x='time', label='default', labelx=None,
                     labely=None ,title=None, shape='.', logx=False,
                     logy=True, base=10):
          '''
          make a simple plot of two columns against each other.
  
          An example would be instance.plot_xtime('PB206', label='PB206 vs t_y'
          Recomend using the plot function DataPlot.plot() it has more
          functionality.
  
          Parameters
          ----------
          Y : string
              Column on Y-axis.
          X : string, optional
              Column on X-axis.  The default is "time".
          label : string, optional
              Legend label.  The default is "default".
          labelX : string, optional
              The label on the X axis.  The default is None.
          labelY : string, optional
              The label on the Y axis.  The default is None.
          title : string, optional
              The Title of the Graph.  The default is None.
          shape : string, optional
              What shape and colour the user would like their plot in.
              The default is '.'.
          logX : boolean, optional
              A boolean of weather the user wants the x axis
              logarithmically.  The default is False.
          logY : boolean, optional
              A boolean of weather the user wants the Y axis
              logarithmically.  The default is True.
          base : integer, optional
              The base of the logarithm.  The default is 10.
  
          Notes
          -----
          For all possable choices visit,
          <http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot.plot>
  
          '''
          if label is 'default':
              lab_str=y
          else:
              lab_str=label
  
          try:
              self.get(x)
          except KeyError:
              x='age'
  
          DataPlot.plot(self,x,y,legend=lab_str,labelx=labelx, labely=labely,
                        title=title, shape=shape,logx=logx, logy=logy, base=base)
          '''
          print X,Y
          xdat=self.get(X)
          ydat=self.get(Y)
          self.xdat = xdat
          self.ydat = ydat
  
  
          plot(xdat,log10(ydat),label=lab_str)
          legend()
          '''