Correct use of NotImplementedError

Author: a-latyshev

doc/demo/demo_nonlinear_heat_equation_part1.py

@@ -291,7 +291,7 @@ def k_external(derivatives):
     elif derivatives == (1,):  # the derivative with respect to the operand `T`
         return dkdT_impl
     else:
-        return NotImplementedError
+        raise NotImplementedError(f"No external function is defined for the requested derivative {derivatives}.")
 
 
 # %% [markdown]

doc/demo/demo_nonlinear_heat_equation_part2.py

@@ -281,7 +281,7 @@ def q_external(derivatives):
     elif derivatives == (0, 1):
         return dqdsigma_impl
     else:
-        return NotImplementedError
+        raise NotImplementedError(f"No external function is defined for the requested derivative {derivatives}.")
 
 
 # %% [markdown]

doc/demo/demo_plasticity_mohr_coulomb.py

@@ -602,7 +602,7 @@ def sigma_external(derivatives):
     if derivatives == (1,):
         return C_tang_impl
     else:
-        return NotImplementedError
+        raise NotImplementedError(f"No external function is defined for the requested derivative {derivatives}.")
 
 
 sigma.external_function = sigma_external

doc/demo/demo_plasticity_von_mises.py

@@ -360,7 +360,7 @@ def sigma_external(derivatives):
     if derivatives == (1,):
         return C_tang_impl
     else:
-        return NotImplementedError
+        raise NotImplementedError(f"No external function is defined for the requested derivative {derivatives}.")
 
 
 sigma.external_function = sigma_external

doc/demo/demo_simple_example.py

@@ -155,7 +155,7 @@ def Ns_external(derivatives):
     elif derivatives == (1,):
         return dNdu_external
     else:
-        return NotImplementedError
+        raise NotImplementedError(f"No external function is defined for the requested derivative {derivatives}.")
 
 
 # %% [markdown]