xlwings is an excellent library to interact with Excel files from Python.
Opening, reading, and writing to Workbooks are as easy as:
>>> from xlwings import Workbook, Sheet, Range, Chart
>>> wb = Workbook() # Creates a connection with a new workbook
>>> Range('A1').value = 'Foo 1'
>>> Range('A1').value
'Foo 1'
You can install it using:
$ pip install xlwings