Excel python COM对象的文档？

I want to use Python and COM to manipulate data and formula in Excel files. I've looked around a couple of modules in python but I have yet to find support for reading formulas. So I am forced to use COM. I'm not sure what to call it but is there something like a documentation for all the classes and methods available on python,COM for excel. There are a few sample codes here and there but I can't seem to find any exhaustive documentation for what I want to do.I want to use Python and COM to manipulate data