NameError: Reggie_Linear_Regression

Starting the new year (2023) off with Reggie. But stuck! In Part 1: Step 5, this is my code (which matches the solution given) …

def calculate_all_error(m, b, datapoints):
total_error = 0
for point in datapoints:
point_error = calculate_error(m, b, point)
total_error += point_error
return total_error

Even after copying and pasting the exact code solution given, I still come up with the following chilling message …

NameError Traceback (most recent call last)
in ()
1 #every point in this dataset lies upon y=x, so the total error should be zero:
2 datapoints = [(1, 1), (3, 3), (5, 5), (-1, -1)]
----> 3 print(calculate_all_error(1, 0, datapoints))
5 #every point in this dataset is 1 unit away from y = x + 1, so the total error should be 4:

NameError: name ‘calculate_all_error’ is not defined

Someone please help? I reviewed the code that I had written in, Part 1: Steps 1 and 2, and they look fine and ran cleanly.

Thank you. It will be a happy new year indeed if I can understand what went wrong?

Run the cell that contains the calculate_all_error function definition.
And afterward, run the cell where you call that function.