How to use the traittypes.Dataset function in traittypes

# Options
    attribution = Unicode().tag(sync=True, o=True)


class Velocity(Layer):
    _view_name = Unicode('LeafletVelocityView').tag(sync=True)
    _model_name = Unicode('LeafletVelocityModel').tag(sync=True)

    zonal_speed = Unicode('', help='Name of the zonal speed in the dataset')
    meridional_speed = Unicode('', help='Name of the meridional speed in the dataset')
    latitude_dimension = Unicode('latitude', help='Name of the latitude dimension in the dataset')
    longitude_dimension = Unicode('longitude', help='Name of the longitude dimension in the dataset')
    units = Unicode(None, allow_none=True)

    data = Dataset().tag(dtype=None, sync=True, to_json=ds_x_to_json)

    # Options
    display_values = Bool(True).tag(sync=True, o=True)
    display_options = Dict({
        'velocityType': 'Global Wind',
        'position': 'bottomleft',
        'emptyString': 'No velocity data',
        'angleConvention': 'bearingCW',
        'displayPosition': 'bottomleft',
        'displayEmptyString': 'No velocity data',
        'speedUnit': 'kt'
        }).tag(sync=True)
    min_velocity = Float(0).tag(sync=True,o=True)
    max_velocity = Float(10).tag(sync=True, o=True)
    velocity_scale = Float(0.005).tag(sync=True, o=True)
    color_scale = List([