Documenting Unknown Data Type In Method Comments for PHP

I have a method in a class that sanitizes data that will be input into a mysql database. It takes two parameters, $data of unknown data type and $html_allowed of bool type. The data type of the $data variable will not initially be known by the method. In the comments, how do 开发者_Python百科I document an unknow data type? Right now my comments look like this:

/**
 *  Sanitizes database input to prevent sql injections.
 *  
 *  @param unknown $data    
 *  @param bool html_allowed
 *  returns unknown $data
 */ 

Is this ok, or is there a better/standardized way?

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You can use @mixed if the argument can be of multiple types.