Add a 'Rectangle' annotation.

def addRectAnnot(self, rect):
        """Add a 'Rectangle' annotation."""
        CheckParent(self)

        val = _fitz.Page_addRectAnnot(self, rect)

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

        return val