jsonResponse = json.loads(strJSONResponse)
strAccessToken = jsonResponse['access_token']
getHeader = {
"Authorization": "Bearer " + strAccessToken
}

r2 = requests.get("https://graph.microsoft.com/v1.0/reports/getTeamsUserActivityUserDetail(date={0})".format(yesterday.strftime('%Y-%m-%d')), headers=getHeader)
strUsageReport = r2.text
print(strUsageReport)

[lisa@host ~]# python genReport.py
Getting stats from 2018-12-15
Report Refresh Date,User Principal Name,Last Activity Date,Is Deleted,Deleted Date,Assigned Products,Team Chat Message Count,Private Chat Message Count,Call Count,Meeting Count,Has Other Action,Report Period

Sending POST request to strURL=https://outlook.office.com/webhook/.../IncomingWebhook/...