code: func (v *VerbalExpression) Not(value string) *VerbalExpression {
  	//return v.add(`(?!(` + quote(value) + `))`)
  	// because Golang doesn't implement ?!
  	// we create a pseudo negative system...
  
  	runes := []rune(quote(value))
  	parts := make([]string, 0)
  	prev := ""
  	for _, r := range runes {
  		parts = append(parts, prev+"[^"+string(r)+"]")
  		prev += string(r)
  	}
  
  	exp := strings.Join(parts, "|")
  	exp = "(?:" + exp + ")*?"
  	return v.add(exp)
  }
docs: // Not invert Find, meaning search something excepting "value". This
  // is different than SomethingBut or AnythingBut that works with a list of
  // caracters. Note that this method is not exactly the same as PCRE system.
  //
  // While PCRE allows: foo(?!bar)baz, "foobarrbaz" matches (note the double r).
  // With our method, this doesn't match. But: "foobarbaz" doen't match (so it's ok).
  // And "fooXXXbaz" matches also.