src/Riak/TimeSeries/Cell.php
public function setDateTimeValue($value = null)
    {
        if ($value != null && !$value instanceof \DateTime) {
            throw new \InvalidArgumentException('Expected a \DateTime object.');
        }

        $this->type = Cell::TIMESTAMP_TYPE;
        $this->value = $value->getTimestamp();

        return $this;
    }
public function setDateTimeValue($value = null)
    {
        if ($value != null && !$value instanceof \DateTime) {
            throw new \InvalidArgumentException('Expected a \DateTime object.');
        }

        $this->type = Cell::TIMESTAMP_TYPE;
        $this->value = $value->getTimestamp();

        return $this;
    }
@param \DateTime $value

@return $this