func Train(words []string) *Model {
	model := &Model{}
	if len(words) == 0 {
		return model
	}
	sm := make(map[string]bool)
	for _, w := range words {
		sm[w] = true
	}
	for cw := range sm {
		model.terms = append(model.terms, cw)
	}
	return model
}
////////////////////////////////////////////////////////////////////////////////// //
Train trains words by given string slice
package spellcheck
import (
	"sort"
	"strings"
	"pkg.re/essentialkaos/ek.v12/mathutil"
)
type Model struct {
	terms []string
}
type suggestItem struct {
	term  string
	score int
}
type suggestItems []*suggestItem
func (s suggestItems) Len() int {
	return len(s)
}
func (s suggestItems) Less(i, j int) bool {
	return s[i].score < s[j].score
}
func (s suggestItems) Swap(i, j int) {
	s[i], s[j] = s[j], s[i]
}
var threshold = 2