def _create_link_from_element(
    anchor,    # type: HTMLElement
    page_url,  # type: str
    base_url,  # type: str
):
    # type: (...) -> Optional[Link]
    """
    Convert an anchor element in a simple repository page to a Link.
    """
    href = anchor.get("href")
    if not href:
        return None

    url = _clean_link(urllib_parse.urljoin(base_url, href))
    pyrequire = anchor.get('data-requires-python')
    pyrequire = unescape(pyrequire) if pyrequire else None

    yanked_reason = anchor.get('data-yanked')
    if yanked_reason:
        # This is a unicode string in Python 2 (and 3).
        yanked_reason = unescape(yanked_reason)

    link = Link(
        url,
        comes_from=page_url,
        requires_python=pyrequire,
        yanked_reason=yanked_reason,
    )

    return link

    Convert an anchor element in a simple repository page to a Link.
    
product/gradle-plugin/src/main/python/pip/_internal/index/collector.py