Here is the help for the "open for access" command. In the Syntax - Parameters section, the first parameter is not specified, but immediately write something in parentheses. In the "write" command, it is done differently. https://developer.apple.com/library/archive/documentation/AppleScript/Conceptual/AppleScriptLangGuide/reference/ASLR_cmds.html#//apple_ref/doc/uid/TP40000983-CH216-SW31
AppleScript Language Guide. open for access. The parameter is not specified in the syntax.
That is the parameter - see the Conventions Used in the Language Guide Introduction.