'Add a Check Version to the transaction.
This command will fail and abort a transaction if the path
does not match the specified version.'

def check(self, path, version):

    if (not isinstance(path, basestring)):
        raise TypeError('path    must    be    a    string')
    if (not isinstance(version, int)):
        raise TypeError('version    must    be    an    int')
    self._add(CheckVersion(_prefix_root(self.client.chroot, path), version))
