import re


def check_pr_url(url):
    """
    check whether the URL of Pull Request is valid
    """
    if url:
        pattern = re.compile(r'https://gitee.com/(open_euler/dashboard/projects/)?'
                             + r'(openeuler|src-openeuler)/([A-Za-z0-9-_]*)/pulls/(\d+$)')
        return pattern.match(url)
    return None