unable to find an inherited method for function ‘exprs’ for signature ‘”list”’

Hi

I get this error in exprs

>DataSeries = getGEO("GSE5847", GSEMatrix = T, AnnotGPL = T, 
                    destdir = "D:/Microarray Data/sharifi.data" )
>expressionData = exprs(DataSeries)
>Error in (function (classes, fdef, mtable)  : 
  unable to find an inherited method for function ‘exprs’ for signature ‘"list"’

How can i fix it?