pyExcelerator and multiple worksheets

[aneesh.goel.rbtx at gmail.com]

I'm using pyExcelerator to take a folder of CSV files and create Excel
workbooks for all of them, then generate an Excel workbook with the
data from all of them.

Everything up until here works great; next, I make a second worksheet
on the last workbook which has summary details regarding the previous
worksheet.  Here I run into a problem.  The Excel form

AVERAGE(Data!E5:E3053)

where Data is the name of the worksheet being referenced (Summary is
the name of the worksheet where the formula is entered) isn't
recognized when I call Formula().  Currently I'm just writing the
string =AVERAGE(Data!E5:E3053) into the cell, but this doesn't get
automatically evaluated; there are multiple instances of this
formatting in use and when used with a larger source folder,
evaluating each cell by hand becomes a significant problem.

Without any documentation for pyExcelerator I turned to the examples
provided, but none of them seemed to use cross-worksheet formulas.
Does anybody know how to fix this, or alternatively know a different
package I could use?  I found xlrd but as that is read-only it doesn't
seem to solve the problem, unless there's some insane and creative way
to use xlrd and pyExcelerator together to solve this.

Thanks in advance!
--Aneesh