framework/data/ActiveDataFilter.php
protected function buildBlockCondition($operator, $condition)
    {
        if (isset($this->queryOperatorMap[$operator])) {
            $operator = $this->queryOperatorMap[$operator];
        }
        return [
            $operator,
            $this->buildCondition($condition),
        ];
    }
protected function buildBlockCondition($operator, $condition)
    {
        if (isset($this->queryOperatorMap[$operator])) {
            $operator = $this->queryOperatorMap[$operator];
        }
        return [
            $operator,
            $this->buildCondition($condition),
        ];
    }
Builds block condition, which consists of a single condition.
It covers such operators as `not`.
@param string $operator operator keyword.
@param mixed $condition raw condition.
@return array actual condition.