AttributeError: Can't get attribute 'Project' on <module '__main__' (built-in)>

Hi there, I am currently running generic worker and having trouble loading the output file generated by the worker. Here’s the code and error:

import pickle
from viktor.external.generic import GenericAnalysis
from utils_2 import Project, UserInputs
user_inputs = UserInputs(soil_profile, footing_input, variables)
files = [("user_inputs.pickle", BytesIO(pickle.dumps(user_inputs)))]

generic_analysis = GenericAnalysis(
output_file = generic_analysis.get_output_file("project.pickle")
project = pickle.load(output_file)
Traceback (most recent call last):
  File "viktor_connector/connector.pyx", line 295, in connector.Job.execute
  File "viktor/core.pyx", line 1918, in viktor.core._handle_job
  File "viktor/core.pyx", line 1864, in viktor.core._handle_job._handle_button
  File "/home/user/src/", line 867, in run_optimizer
    project = pickle.load(output_file)
AttributeError: Can't get attribute 'Project' on <module '__main__' (built-in)>