NameError: name 'util' is not defined

When running any of the nonlinear examples, I get the following error:

Traceback (most recent call last):
  File "/Users/gdelimpaltadak/Desktop/Material/Code/Python/Sentient/etc2traffic.py", line 72, in <module>
    traffic = construct_nonlinearETC_traffic_from_file(input_file)
  File "/Users/gdelimpaltadak/Desktop/Material/Code/Python/Sentient/sentient/util/construct_from_file_nonlinearETC.py", line 251, in construct_nonlinearETC_traffic_from_file
    traffic = abstr.TrafficModelNonlinearETC(dict_key_to_attrs['Dynamics'], dict_key_to_attrs['Triggering Condition'], state_vector,
  File "/Users/gdelimpaltadak/Desktop/Material/Code/Python/Sentient/sentient/Abstractions/NonlinearETC/TrafficModelNonlinearETC.py", line 149, in __init__
    if not util.test_homogeneity(dynamics, state):
NameError: name 'util' is not defined