code: private function appendBind($part, $bind) 
  	{
  		if ($bind === false) return $this;
  		
  		if (!is_array($bind)) $bind = [$bind]; 
  		
  		if (!$this->bind[$part]) 
  		{
  			$this->bind[$part] = $bind;
  		}
  		else 
  		{
  			$this->bind[$part] = array_merge($this->bind[$part], $bind);
  		}
  		
  		return $this;
  	}
docs: Append bind values to given part.
  @param int $part Part to append to.
  @param mixed|array|false $bind
  @return static