code: func getRawPattern(rawPattern string) string {
  	rawPattern = strings.Replace(rawPattern, ":int", "", -1)
  	rawPattern = strings.Replace(rawPattern, ":string", "", -1)
  
  	for {
  		startIdx := strings.Index(rawPattern, "(")
  		if startIdx == -1 {
  			break
  		}
  
  		closeIdx := strings.Index(rawPattern, ")")
  		if closeIdx > -1 {
  			rawPattern = rawPattern[:startIdx] + rawPattern[closeIdx+1:]
  		}
  	}
  	return rawPattern
  }
docs: // getRawPattern removes all regexp but keeps wildcards for building URL path.