Make IndexError more verbose.

Made #97 easier to trouble-shoot.
jensengroup · Nov 22, 2020 · 272329d · 272329d
1 parent 67039aa
commit 272329d
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/propka/group.py b/propka/group.py
@@ -765,7 +765,13 @@ def setup_atoms(self):
         the_oxygen = self.atom.get_bonded_elements('O')
         the_nitrogen = self.atom.get_bonded_elements('N')
         # add protons to the nitrogen
-        PROTONATOR.protonate_atom(the_nitrogen[0])
+        try:
+            PROTONATOR.protonate_atom(the_nitrogen[0])
+        except IndexError:
+            raise IndexError(
+                "Unable to find bonded elements for the nitrogen associated "
+                "with amide group %s" % self.atom
+            )
         the_hydrogens = the_nitrogen[0].get_bonded_elements('H')
         # set the center using the oxygen and nitrogen amide atoms
         self.set_center(the_oxygen+the_nitrogen)