def METHOD_NAME(self):
    """
    Text representation of a scatter plot graphics primitive.
    EXAMPLES::
        sage: import numpy
        sage: from sage.plot.scatter_plot import ScatterPlot
        sage: ScatterPlot(numpy.array([0,1,2]), numpy.array([3.5,2,5.1]), {})
        Scatter plot graphics primitive on 3 data points
    """
    return 'Scatter plot graphics primitive on %s data points' % len(self.xdata)