func (decl *Declaration) StringWithImportant(option bool) string {
	result := fmt.Sprintf("%s: %s", decl.Property, decl.Value)
	if option && decl.Important {
		result += " !important"
	}
	result += ";"
	return result
}
StringWithImportant returns string representation with optional !important part
package css
import "fmt"
type Declaration struct {
	Property  string
	Value     string
	Important bool
}
func NewDeclaration() *Declaration {
	return &Declaration{}
}
func (decl *Declaration) String() string {
	return decl.StringWithImportant(true)
}