unable to download the data

I am a beginner to python and obspy as well. I wish to download continous noise data through IRIS using obspy. After following the documentation, I gave the restrictions (network, station, channels, location) but stiil I am getting an error message saying “restrictions” is not defined. It would be highly appreciated if you help me regarding this issue.
Below I am mentioning how I went through…

import obspy
from obspy.clients.fdsn.mass_downloader import Restrictions, MassDownloader
restrictions = Restrictions(
starttime=obspy.UTCDateTime(2012, 1, 1),