'return AxisInfo instance for x and unit'

@staticmethod
def axisinfo(unit, axis):

    if (unit == radians):
        return units.AxisInfo(majloc=ticker.MultipleLocator(base=(np.pi / 2)), majfmt=ticker.FuncFormatter(rad_fn), label=unit.fullname)
    elif (unit == degrees):
        return units.AxisInfo(majloc=ticker.AutoLocator(), majfmt=ticker.FormatStrFormatter('$%i^\\circ$'), label=unit.fullname)
    elif (unit is not None):
        if hasattr(unit, 'fullname'):
            return units.AxisInfo(label=unit.fullname)
        elif hasattr(unit, 'unit'):
            return units.AxisInfo(label=unit.unit.fullname)
    return None
