How to use CDO objects to send email with .mht file as body but not as attachment

I am using CDO as below, to email the output .mht file upon execution of project as an attachment

However I wish the contents of .mht file to be in email body. How can I do that?

def SendEmail(mFrom, mTo, mSubject, mBody, mAttach):
    try:
        schema = "http://schemas.microsoft.com/cdo/configuration/"
        mConfig = Sys.OleObject["CDO.Configuration"]
        mConfig.Fields.Item[schema + "sendusing"] = 2 
        mConfig.Fields.Item[schema + "smtpserver"] = "something.com"
        mConfig.Fields.Item[schema + "smtpserverport"] = 25 
        mConfig.Fields.Update();
        mMessage = Sys.OleObject["CDO.Message"] 
        mMessage.Configuration = mConfig;
        mMessage.From = "someone@somewhere.com"
        mMessage.To = "anotherone@somewhere.com"
        mMessage.Subject = "Subject"
        mMessage.HTMLBody = "Body"
        mMessage.AddAttachment("file:///C:/Report.mht")
        mMessage.Attachments.Item[1].ContentMediaType="application/octet-stream"
        mMessage.Send();
    except Exception as e:
        Log.Error("E-mail cannot be sent", str(e))
        return False
    Log.Message("Message was sent successfully to anotherone@somewhere.com")
    return True