Add a 'FileAttachment' annotation at location 'point'.

def addFileAnnot(self, point, buffer, filename, ufilename=None, desc=None):
        """Add a 'FileAttachment' annotation at location 'point'."""
        CheckParent(self)

        val = _fitz.Page_addFileAnnot(self, point, buffer, filename, ufilename, desc)

        if not val: return
        val.thisown = True
        val.parent = weakref.proxy(self)
        self._annot_refs[id(val)] = val

        return val