old_contents: """Core pep438 utility functions"""
  from __future__ import unicode_literals
  
  import requests
  import xmlrpclib
  import lxml.html
  from reqfileparser import parse
  
  
  def valid_package(package_name):
      """Return bool if package_name is a valid package on PyPI"""
      response = requests.head('https://pypi.python.org/pypi/%s' % package_name)
      if response.status_code != 404:
          response.raise_for_status()
      return response.status_code != 404
  
  
  def get_urls(package_name):
      """Return list of URLs on package's PyPI page that would be crawled"""
      response = requests.get('https://pypi.python.org/simple/%s' % package_name)
      response.raise_for_status()
      page = lxml.html.fromstring(response.content)
      crawled_urls = {link.get('href') for link in page.xpath('//a')
                      if link.get('rel') in ("homepage", "download")}
      return crawled_urls
  
  
  def get_pypi_packages(fileobj):
      """Return all PyPI-hosted packages from file-like object"""
      return [p['name'] for p in parse(fileobj) if not p.get('uri')]
  
  
  def get_pypi_user_packages(user):
      client = xmlrpclib.ServerProxy('https://pypi.python.org/pypi')
      return [x[1] for x in client.user_packages(user)]
  
new_contents: """Core pep438 utility functions"""
  from __future__ import unicode_literals
  
  import requests
  import xmlrpclib
  import lxml.html
  from requirements import parse
  
  
  def valid_package(package_name):
      """Return bool if package_name is a valid package on PyPI"""
      response = requests.head('https://pypi.python.org/pypi/%s' % package_name)
      if response.status_code != 404:
          response.raise_for_status()
      return response.status_code != 404
  
  
  def get_urls(package_name):
      """Return list of URLs on package's PyPI page that would be crawled"""
      response = requests.get('https://pypi.python.org/simple/%s' % package_name)
      response.raise_for_status()
      page = lxml.html.fromstring(response.content)
      crawled_urls = {link.get('href') for link in page.xpath('//a')
                      if link.get('rel') in ("homepage", "download")}
      return crawled_urls
  
  
  def get_pypi_packages(fileobj):
      """Return all PyPI-hosted packages from file-like object"""
      return [p['name'] for p in parse(fileobj) if not p.get('uri')]
  
  
  def get_pypi_user_packages(user):
      client = xmlrpclib.ServerProxy('https://pypi.python.org/pypi')
      return [x[1] for x in client.user_packages(user)]
  
subject: Fix requirements-parser import