Make Particle Type errors into a warning and a NotImplementedError

tests/inputs/test_not_imp.imcnp

@@ -0,0 +1,48 @@
+A test with a default importance (Not Implemented)
+C cells
+c
+1 1 20
+         -1000  $ dollar comment
+     U=350 trcl=5
+     imp:n,p=1  $ imp:e should default to 1
+2 2 8
+      -1005
+     imp:n,p=1  $ imp:e should default to 1
+3 3 -1
+      1000 1005 -1010
+     imp:n=3    $ imp:e and imp:p should default to 1
+99 0
+      1010
+     imp:n=9    $ imp:e should default to 1
+     imp:p=0
+5 0 
+      #99
+     imp:n=0    $ imp:e should default to 0
+     imp:p=0
+c foo end comment
+
+C surfaces
+1000 SO 1
+1005 RCC 0 1.5 -0.5 0 0 1 0.25
+1010 SO 3
+
+C data
+C materials
+C UO2 5 atpt enriched
+m1        92235.80c           5 &
+92238.80c          95
+C Iron
+m2        26054.80c        5.85
+          26056.80c       91.75
+          26057.80c        2.12
+          26058.80c        0.28
+C water
+m3        1001.80c           2
+           8016.80c           1
+MT3 lwtr.23t
+C execution
+ksrc 0 0 0
+kcode 100000 1.000 50 1050
+phys:p j 1 2j 1
+mode n p e
+

tests/test_importance.py

@@ -6,6 +6,7 @@
 from montepy.errors import *
 from montepy.input_parser import mcnp_input, block_type
 import os
+import io
 import pytest
 
 
@@ -176,6 +177,13 @@ def test_importance_merge():
         imp1.merge(imp2)
 
 
-def tests_redundant_importance():
+def test_redundant_importance():
     with pytest.raises(MalformedInputError):
         montepy.read_input(os.path.join("tests", "inputs", "test_imp_redundant.imcnp"))
+
+
+def test_not_imp():
+    prob = montepy.read_input(os.path.join("tests", "inputs", "test_not_imp.imcnp"))
+    prob.print_in_data_block["imp"] = True
+    with pytest.raises(NotImplementedError):
+        prob.write_problem(io.StringIO())