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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def getToC(doc, simple = True):
 """Create a table of contents. Args: simple: a bool to control output. Returns a list, where each entry consists of outline level, title, page number and link destination (if simple = False). For details see PyMuPDF's documentation. """


    def recurse(olItem, liste, lvl):
        '''Recursively follow the outline item chain and record item information in a list.'''
        while olItem:
            if olItem.title:
                title = olItem.title
            else:
                title = " "

            if not olItem.isExternal:
                if olItem.uri:
                    page = olItem.page + 1
                else:
                    page = -1
            else:
                page = -1

            if not simple:
                link = getLinkDict(olItem)
                liste.append([lvl, title, page, link])
            else:
                liste.append([lvl, title, page])

            if olItem.down:
                liste = recurse(olItem.down, liste, lvl+1)
            olItem = olItem.next
        return liste

    # check if document is open and not encrypted
    if doc.isClosed:
        raise ValueError("illegal operation on closed document")

    olItem = doc.outline

    if not olItem: return []
    lvl = 1
    liste = []
    return recurse(olItem, liste, lvl)