drscheme:unit:open-drscheme-window in DrScheme Tools Functions
(drscheme:unit:open-drscheme-window)-> (is-a?/cdrscheme:unit:frame%)
(drscheme:unit:open-drscheme-window-> (is-a?/cfilename)drscheme:unit:frame%)
filename: (union string? false/c)Opens a drscheme frame that displays
filename, or nothing iffilenameis#for not supplied.