code: func _boolf(i interface{}) (bool, bool) {
  
  	if i2, ok := i.(*Graph); ok {
  		// i2 can still be nil (of type *Graph!)
  		if i2 == nil {
  			return false, false
  		}
  		i = i2.This
  	}
  
  	switch v := i.(type) {
  	case []byte:
  		s := string(v)
  
  		if falseStr == s {
  			return false, true
  		}
  		if trueStr == s {
  			return true, true
  		}
  		return false, false
  	case string:
  		if falseStr == v {
  			return false, true
  		}
  		if trueStr == v {
  			return true, true
  		}
  		return false, false
  	case bool:
  		return v, true
  	}
  
  	return false, false
  }
docs: // _boolf converts an interface{} to a boolean if possible.