```
# code removed - mentor edit
```

```
# Compute cost with some initial values for paramaters w, b
initial_w = 2
initial_b = 1
Cost = compute_cost(x_train, y_train, initial_w, initial_b)
print(type(Cost))
print(f'Cost at initial w: {Cost:.3f}')
# Public tests
from public_tests import *
compute_cost_test(compute_cost)
```

**Output:**

**UnboundLocalError** Traceback (most recent call last) **d:\Courses\Machine Learning\Files(practice)\Files\home\jovyan\work\C1_W2_Linear_Regression.ipynb Cell 23** in <cell line: 5>**()** 2 initial_w = 2 3 initial_b = 1 **----> 5** Cost = compute_cost(x_train, y_train, initial_w, initial_b) 6 print(type(Cost)) 7 print(f’Cost at initial w: {Cost:.3f}') **d:\Courses\Machine Learning\Files(practice)\Files\home\jovyan\work\C1_W2_Linear_Regression.ipynb Cell 23** in compute_cost**(x, y, w, b)** 26 f_wb=w*x[i]+b 27 cost =(f_wb-y[i])**2 —> 28 cost_sum=cost_sum+cost 29 J_wb =(1/2*m)*cost_sum 31 ### END CODE HERE ###

**UnboundLocalError**: local variable ‘cost_sum’ referenced before assignment