Here is a very simple example of how to retrieve a report from Amazon (assuming you already have a report ID from a different request, or from seller central) using the python-amazon-mws wrapper.
from mws import mws
access_key = 'accesskey' #replace with your access key
merchant_id = 'merchantid' #replace with your merchant id
secret_key = 'secretkey' #replace with your secret key
reportid = '123456' #replace with report id
x = mws.Reports(access_key=access_key, secret_key=secret_key, account_id=merchant_id)
report = x.get_report(report_id=reportid)
response_data = report.original
print response_data