when I run the code I receive this error what is the problem?

forward_propagation(X, parameters) is a helper function, and is in You do not need to look into this.
The problem is, “parameters” in here, which is created by your “initialize_parameters_zeros()”.
At the unit test, “layer_dims” was 3. So, you created “W1”, “b1”, “W2” and “b2”. In this test, “layer_dims” is 4. So, you need to create “W1”, “b1”, “W2”, “b2”, “W3”, and b3. But, this helper function could not find “W3”.
Please double check your implementation for initialize_parameters_zero(), and ensure that it can create “W1”, “b1”, … “Wn”, “bn”, … corresponding to the layer number passed as “layers_dims”.