attach extends attach function,
rank extends rank function,
stdev adds stdev function,
termPlot adds term plot function,
volatility adds volatility function. }## S3 method for class 'default':
stdev(x, na.rm = FALSE)## S3 method for class 'default':
termPlot(model, \dots)
## S3 method for class 'default':
volatility(object, \dots)