Python : NameError: name 'total_wait' is not defined

[metulburr]

plt.plot(total_wait)

total_plot doesnt exist, but there is a class attribute for Simulation
s is your Simulation object in which has an attribute total_wait. Within a class definition you use self.total_wait, outside of the class you need to refer to it using the object, in this case 's'

s = Simulation()

try this....

plt.plot(s.total_wait)