wrong error diagnostic message
There is a confusion at the diagnostic level. When calling 

> pd.io.parsers.ExcelFile.parse(xl)

where xl is of type pd.ExcelFile()

I get the message: _TypeError_: unbound method parse() must be called with ExcelFile instance as first argument (got ExcelFile instance instead)

and the message should read: unbound method parse() must be called with _ExcelSheet name_ as first argument 
