text: import matplotlib
  matplotlib.rcParams['units'] = True
  from matplotlib.cbook import iterable, is_numlike
  import matplotlib.units as units
  import matplotlib.dates as dates
  import matplotlib.ticker as ticker
  import datetime
  
  class DateConverter(units.ConversionInterface):
  
      def axisinfo(unit):
          'return the unit AxisInfo'
          if unit=='date':
              majloc = dates.AutoDateLocator()
              majfmt = dates.AutoDateFormatter(majloc)
              return units.AxisInfo(
                  majloc = majloc,
                  majfmt = majfmt,
                  label='date',
                  )
          else: return None
      axisinfo = staticmethod(axisinfo)
  
      def convert(value, unit):
          if units.ConversionInterface.is_numlike(value): return value
          return dates.date2num(value)
      convert = staticmethod(convert)
  
      def default_units(x):
          'return the default unit for x or None'
          return 'date'
      default_units = staticmethod(default_units)
  
  
  units.registry[datetime.date] = DateConverter()
  units.registry[datetime.datetime] = DateConverter()
  