func (params Params) String() string {
	if len(params) < 1 {
		return ""
	}
	p := make([]string, 0, len(params))
	for k, v := range params {
		p = append(p, fmt.Sprintf("%s=%s", k, v))
	}
	return fmt.Sprintf("?%s", strings.Join(p, "&"))
}
String returns parameters as string with the format ?param1=val1&param2=val2, parameter order is not guaranteed
package helpers
import (
	"fmt"
	"strings"
)
type Params map[string]string