diff -r 16dae12ac0f0 -r 97de6058109e parse.py
--- a/parse.py	Fri Sep 18 20:46:26 2020 +0300
+++ b/parse.py	Fri Sep 18 20:59:59 2020 +0300
@@ -41,7 +41,13 @@
     def find_first_header_object(self, object_type):
         return self.find_header_object(object_type, 0)
     def find_header_object(self, object_type, n):
-        return self.body[self.header.occurrences[object_type][n]]
+        try:
+            return self.body[self.header.occurrences[object_type][n]]
+        except IndexError:
+            raise KeyError(str.format(
+                '{type} not found in header',
+                type = object_type
+            ))
 
 def model_vertices(
     model,