code: protected function setPart($part, $sql, $bind = false)
  	{
  		$this->parts[$part] = $sql;
  		
  		if (is_array($bind)) 		$this->bind[$part] = $bind;
  		else if ($bind === false)	$this->bind[$part] = false;
  		else						$this->bind[$part] = [$bind];
  		
  		return $this;
  	}
docs: Override part value.
  @param int $part Part to set.
  @param string|array $sql Value to set for this part. Use only for parts that will not
  be appended to. Otherwise pass as array.
  @param array|bool $bind Array of bind values if any.
  @return static