def check_pypi_updates(dependencies):
    """Return a list of dependencies to upgrade."""
    dependencies_up_to_date = []
    for dependency in dependencies.get('pypi', []):
        # get latest version from PyPI api
        try:
            latest_version = get_latest_version_number(dependency.project_name)
        except Exception as error:
            logger.warning("--check-updates command will be aborted. Error: %s", error)
            return dependencies
        # get required version
        required_version = None
        if dependency.specs:
            _, required_version = dependency.specs[0]

        if required_version:
            dependencies_up_to_date.append(dependency)
            if latest_version > required_version:
                logger.info("There is a new version of %s: %s",
                            dependency.project_name, latest_version)
            elif latest_version < required_version:
                logger.warning("The requested version for %s is greater "
                               "than latest found in PyPI: %s",
                               dependency.project_name, latest_version)
            else:
                logger.info("The requested version for %s is the latest one in PyPI: %s",
                            dependency.project_name, latest_version)
        else:
            project_name_plus = "{}=={}".format(dependency.project_name, latest_version)
            dependencies_up_to_date.append(pkg_resources.Requirement.parse(project_name_plus))
            logger.info("The latest version of %r is %s and will use it.",
                        dependency.project_name, latest_version)

    dependencies["pypi"] = dependencies_up_to_date
    return dependencies
Return a list of dependencies to upgrade.