<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def parse_footnote(document, container, elem):
    "Parse the footnote element."

    _rid = elem.attrib[_name('{{{w}}}id')]
    foot = doc.Footnote(_rid)
    container.elements.append(foot)