How to handle triple-nested quotes in Zsh?

I’ve been setting an alias that running Apple Script on Terminal. As below:

alias playda="osascript -e 'tell application "QuickTime Player"
    activate
    set thisFile to open POSIX file "path.m4a"
    play thisFile
end tell'"

And Zsh always reports an error:

.zshrc:19: number expected

I think it relates to the quotes. Could anyone show me how to handle this, please?

Thank you very much!