Python Package Name (PEP 508)

const re = new RegExp("^[A-Za-z0-9](?:[A-Za-z0-9._\\-]*[A-Za-z0-9])?$", "");
const input = "requests";
const match = input.match(re);
console.log(match ? match[0] : null);

import re

pattern = re.compile(r"^[A-Za-z0-9](?:[A-Za-z0-9._\-]*[A-Za-z0-9])?$")
input_text = "requests"
for m in pattern.finditer(input_text):
    print(m.group(0))

package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`^[A-Za-z0-9](?:[A-Za-z0-9._\-]*[A-Za-z0-9])?$`)
	input := `requests`
	for _, match := range re.FindAllString(input, -1) {
		fmt.Println(match)
	}
}