p.SetConfig unavailable

[apuatcfbd]

Hello,
Thank you for making this wonderful lib, I'm facing some issues setting config to the printer,

In the code snipet in the documentation p.SetConfig(escpos.ConfigEpsonTMT20II) is missing,
Following is the error

# command-line-arguments
./main.go:16:4: p.SetConfig undefined (type *escpos.Escpos has no field or method SetConfig)
./main.go:16:21: undefined: escpos.ConfigEpsonTMT20II

How to set config to the printer?