'append the given expression to this select() construct\'s WHERE
criterion.
The expression will be joined to existing WHERE criterion via AND.
This is an **in-place** mutation method; the
:meth:`~.Select.where` method is preferred, as it provides standard
:term:`method chaining`.'

def append_whereclause(self, whereclause):

    self._reset_exported()
    self._whereclause = and_(True_._ifnone(self._whereclause), whereclause)
