clear_atomic now clears sequences from segments when they are the wrong length

mrdna/segmentmodel.py

@@ -1573,6 +1573,10 @@ class SegmentModel(ArbdModel):
             for d in ('fwd','rev'):
                 seg.strand_pieces[d] = []
         self._generate_strands()
+        ## Clear sequence if needed
+        for seg in self.segments:
+            if seg.sequence is not None and len(seg.sequence) != seg.num_nt:
+                seg.sequence = None
 
     def clear_beads(self):
         return self._clear_beads()
@@ -2428,7 +2432,7 @@ class SegmentModel(ArbdModel):
                 for d in ('fwd','rev'):
                     seg.strand_pieces[d] = []
         except:
-            ...
+            pass
         self.strands = strands = []
 
         """ Ensure unconnected ends have 5prime Location objects """