What am I doing worng? Tried in both the windows prompt and git bash on windows 7

I have python installed and I am getting this error:

$ npm install nodegit
......

nodegit@0.1.0 install c:\Users\sebas\Desktop\adchievefeed\node_modules\nodegit

node install.js

c:\Users\sebas\Desktop\adchievefeed\node_modules\nodegit\install.js:82
throw new Error('Python is required to build libgit2');
^
Error: Python is required to build libgit2
at c:\Users\sebas\Desktop\adchievefeed\node_modules\nodegit\install.js:82:27

at ChildProcess.exithandler (child_process.js:641:7)
at ChildProcess.EventEmitter.emit (events.js:98:17)
at maybeClose (child_process.js:735:16)
at Process.ChildProcess._handle.onexit (child_process.js:802:5)

npm ERR! weird error 8
npm ERR! not ok code 0

sebas@SEBAS-PC ~/Desktop/adchievefeed
$ which python
/c/Python33/python