': Convert value using unit to a float.  If value is a sequence, return
the converted sequence.
= INPUT VARIABLES
- value   The value or list of values that need to be converted.
- unit    The units to use for a axis with Epoch data.
= RETURN VALUE
- Returns the value parameter converted to floats.'

@staticmethod
def convert(value, unit, axis):

    import matplotlib.testing.jpl_units as U
    isNotUnitDbl = True
    if (iterable(value) and (not isinstance(value, six.string_types))):
        if (len(value) == 0):
            return []
        else:
            return [UnitDblConverter.convert(x, unit, axis) for x in value]
    if isinstance(value, U.UnitDbl):
        isNotUnitDbl = False
    if (isNotUnitDbl and units.ConversionInterface.is_numlike(value)):
        return value
    if (unit == None):
        unit = UnitDblConverter.default_units(value, axis)
    if (isinstance(axis.axes, polar.PolarAxes) and (value.type() == u'angle')):
        return value.convert(u'rad')
    return value.convert(unit)
